diff --git a/ChangeLog b/ChangeLog
index 184bd09..a6d4adf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,116 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
+= mbed TLS 2.26.0 branch released 2021-03-08
+
+API changes
+   * Renamed the PSA Crypto API output buffer size macros to bring them in line
+     with version 1.0.0 of the specification.
+   * The API glue function mbedtls_ecc_group_of_psa() now takes the curve size
+     in bits rather than bytes, with an additional flag to indicate if the
+     size may have been rounded up to a whole number of bytes.
+   * Renamed the PSA Crypto API AEAD tag length macros to bring them in line
+     with version 1.0.0 of the specification.
+
+Default behavior changes
+   * In mbedtls_rsa_context objects, the ver field was formerly documented
+     as always 0. It is now reserved for internal purposes and may take
+     different values.
+
+New deprecations
+   * PSA_KEY_EXPORT_MAX_SIZE, PSA_HASH_SIZE, PSA_MAC_FINAL_SIZE,
+     PSA_BLOCK_CIPHER_BLOCK_SIZE, PSA_MAX_BLOCK_CIPHER_BLOCK_SIZE and
+     PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN have been renamed, and the old names
+     deprecated.
+   * PSA_ALG_AEAD_WITH_DEFAULT_TAG_LENGTH and PSA_ALG_AEAD_WITH_TAG_LENGTH
+     have been renamed, and the old names deprecated.
+
+Features
+   * The PSA crypto subsystem can now use HMAC_DRBG instead of CTR_DRBG.
+     CTR_DRBG is used by default if it is available, but you can override
+     this choice by setting MBEDTLS_PSA_HMAC_DRBG_MD_TYPE at compile time.
+     Fix #3354.
+   * Automatic fallback to a software implementation of ECP when
+     MBEDTLS_ECP_xxx_ALT accelerator hooks are in use can now be turned off
+     through setting the new configuration flag MBEDTLS_ECP_NO_FALLBACK.
+   * The PSA crypto subsystem can now be configured to use less static RAM by
+     tweaking the setting for the maximum amount of keys simultaneously in RAM.
+     MBEDTLS_PSA_KEY_SLOT_COUNT sets the maximum number of volatile keys that
+     can exist simultaneously. It has a sensible default if not overridden.
+   * Partial implementation of the PSA crypto driver interface: Mbed TLS can
+     now use an external random generator instead of the library's own
+     entropy collection and DRBG code. Enable MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG
+     and see the documentation of mbedtls_psa_external_get_random() for details.
+   * Applications using both mbedtls_xxx and psa_xxx functions (for example,
+     applications using TLS and MBEDTLS_USE_PSA_CRYPTO) can now use the PSA
+     random generator with mbedtls_xxx functions. See the documentation of
+     mbedtls_psa_get_random() for details.
+   * In the PSA API, the policy for a MAC or AEAD algorithm can specify a
+     minimum MAC or tag length thanks to the new wildcards
+     PSA_ALG_AT_LEAST_THIS_LENGTH_MAC and
+     PSA_ALG_AEAD_WITH_AT_LEAST_THIS_LENGTH_TAG.
+
+Security
+   * Fix a security reduction in CTR_DRBG when the initial seeding obtained a
+     nonce from entropy. Applications were affected if they called
+     mbedtls_ctr_drbg_set_nonce_len(), if they called
+     mbedtls_ctr_drbg_set_entropy_len() with a size that was 3/2 times the key
+     length, or when the entropy module uses SHA-256 and CTR_DRBG uses AES-256.
+     In such cases, a random nonce was necessary to achieve the advertised
+     security strength, but the code incorrectly used a constant instead of
+     entropy from the nonce.
+     Found by John Stroebel in #3819 and fixed in #3973.
+   * Fix a buffer overflow in mbedtls_mpi_sub_abs() when calculating
+     |A| - |B| where |B| is larger than |A| and has more limbs (so the
+     function should return MBEDTLS_ERR_MPI_NEGATIVE_VALUE). Only
+     applications calling mbedtls_mpi_sub_abs() directly are affected:
+     all calls inside the library were safe since this function is
+     only called with |A| >= |B|. Reported by Guido Vranken in #4042.
+   * Fix an errorneous estimation for an internal buffer in
+     mbedtls_pk_write_key_pem(). If MBEDTLS_MPI_MAX_SIZE is set to an odd
+     value the function might fail to write a private RSA keys of the largest
+     supported size.
+     Found by Daniel Otte, reported in #4093 and fixed in #4094.
+   * Fix a stack buffer overflow with mbedtls_net_poll() and
+     mbedtls_net_recv_timeout() when given a file descriptor that is
+     beyond FD_SETSIZE. Reported by FigBug in #4169.
+   * Guard against strong local side channel attack against base64 tables by
+     making access aceess to them use constant flow code.
+
+Bugfix
+   * Fix use-after-scope error in programs/ssl/ssl_client2.c and ssl_server2.c
+   * Fix memory leak that occured when calling psa_close_key() on a
+     wrapped key with MBEDTLS_PSA_CRYPTO_SE_C defined.
+   * Fix an incorrect error code if an RSA private operation glitched.
+   * Fix a memory leak in an error case in psa_generate_derived_key_internal().
+   * Fix a resource leak in CTR_DRBG and HMAC_DRBG when MBEDTLS_THREADING_C
+     is enabled, on platforms where initializing a mutex allocates resources.
+     This was a regression introduced in the previous release. Reported in
+     #4017, #4045 and #4071.
+   * Ensure that calling mbedtls_rsa_free() or mbedtls_entropy_free()
+     twice is safe. This happens for RSA when some Mbed TLS library functions
+     fail. Such a double-free was not safe when MBEDTLS_THREADING_C was
+     enabled on platforms where freeing a mutex twice is not safe.
+   * Fix a resource leak in a bad-arguments case of mbedtls_rsa_gen_key()
+     when MBEDTLS_THREADING_C is enabled on platforms where initializing
+     a mutex allocates resources.
+   * Fixes a bug where, if the library was configured to include support for
+     both the old SE interface and the new PSA driver interface, external keys were
+     not loaded from storage. This was fixed by #3996.
+   * This change makes 'mbedtls_x509write_crt_set_basic_constraints'
+     consistent with RFC 5280 4.2.1.9 which says: "Conforming CAs MUST
+     include this extension in all CA certificates that contain public keys
+     used to validate digital signatures on certificates and MUST mark the
+     extension as critical in such certificates." Previous to this change,
+     the extension was always marked as non-critical. This was fixed by
+     #3698.
+
+Changes
+   * A new library C file psa_crypto_client.c has been created to contain
+     the PSA code needed by a PSA crypto client when the PSA crypto
+     implementation is not included into the library.
+   * On recent enough versions of FreeBSD and DragonFlyBSD, the entropy module
+     now uses the getrandom syscall instead of reading from /dev/urandom.
+
 = mbed TLS 2.25.0 branch released 2020-12-11
 
 API changes
diff --git a/ChangeLog.d/drbg-mutex.txt b/ChangeLog.d/drbg-mutex.txt
deleted file mode 100644
index 3ac5abf..0000000
--- a/ChangeLog.d/drbg-mutex.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Bugfix
-   * Fix a resource leak in CTR_DRBG and HMAC_DRBG when MBEDTLS_THREADING_C
-     is enabled, on platforms where initializing a mutex allocates resources.
-     This was a regression introduced in the previous release. Reported in
-     #4017, #4045 and #4071.
diff --git a/ChangeLog.d/fix_psa_crypto_leak.txt b/ChangeLog.d/fix_psa_crypto_leak.txt
deleted file mode 100644
index 6f9e5fe..0000000
--- a/ChangeLog.d/fix_psa_crypto_leak.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-Bugfix
-   * Fix a memory leak in an error case in psa_generate_derived_key_internal().
diff --git a/ChangeLog.d/getentropy.txt b/ChangeLog.d/getentropy.txt
deleted file mode 100644
index 460798f..0000000
--- a/ChangeLog.d/getentropy.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-Changes
-   * On recent enough versions of FreeBSD and DragonFlyBSD, the entropy module
-     now uses the getrandom syscall instead of reading from /dev/urandom.
diff --git a/ChangeLog.d/issue3819.txt b/ChangeLog.d/issue3819.txt
deleted file mode 100644
index e41520f..0000000
--- a/ChangeLog.d/issue3819.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-Security
-   * Fix a security reduction in CTR_DRBG when the initial seeding obtained a
-     nonce from entropy. Applications were affected if they called
-     mbedtls_ctr_drbg_set_nonce_len(), if they called
-     mbedtls_ctr_drbg_set_entropy_len() with a size that was 3/2 times the key
-     length, or when the entropy module uses SHA-256 and CTR_DRBG uses AES-256.
-     In such cases, a random nonce was necessary to achieve the advertised
-     security strength, but the code incorrectly used a constant instead of
-     entropy from the nonce.
-     Found by John Stroebel in #3819 and fixed in #3973.
diff --git a/ChangeLog.d/issue4093.txt b/ChangeLog.d/issue4093.txt
deleted file mode 100644
index f6985cf..0000000
--- a/ChangeLog.d/issue4093.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-Security
-   * Fix an errorneous estimation for an internal buffer in
-     mbedtls_pk_write_key_pem(). If MBEDTLS_MPI_MAX_SIZE is set to an odd
-     value the function might fail to write a private RSA keys of the largest
-     supported size.
-     Found by Daniel Otte, reported in #4093 and fixed in #4094.
diff --git a/ChangeLog.d/mbedtls_ecc_group_of_psa.txt b/ChangeLog.d/mbedtls_ecc_group_of_psa.txt
deleted file mode 100644
index bce4c66..0000000
--- a/ChangeLog.d/mbedtls_ecc_group_of_psa.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-API changes
-   * The API glue function mbedtls_ecc_group_of_psa() now takes the curve size
-     in bits rather than bytes, with an additional flag to indicate if the
-     size may have been rounded up to a whole number of bytes.
diff --git a/ChangeLog.d/mbedtls_psa_get_random.txt b/ChangeLog.d/mbedtls_psa_get_random.txt
deleted file mode 100644
index f6e6b09..0000000
--- a/ChangeLog.d/mbedtls_psa_get_random.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-Features
-   * Partial implementation of the PSA crypto driver interface: Mbed TLS can
-     now use an external random generator instead of the library's own
-     entropy collection and DRBG code. Enable MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG
-     and see the documentation of mbedtls_psa_external_get_random() for details.
-   * Applications using both mbedtls_xxx and psa_xxx functions (for example,
-     applications using TLS and MBEDTLS_USE_PSA_CRYPTO) can now use the PSA
-     random generator with mbedtls_xxx functions. See the documentation of
-     mbedtls_psa_get_random() for details.
diff --git a/ChangeLog.d/mpi_sub_abs.txt b/ChangeLog.d/mpi_sub_abs.txt
deleted file mode 100644
index 9f34ee7..0000000
--- a/ChangeLog.d/mpi_sub_abs.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-Security
-   * Fix a buffer overflow in mbedtls_mpi_sub_abs() when calculating
-     |A| - |B| where |B| is larger than |A| and has more limbs (so the
-     function should return MBEDTLS_ERR_MPI_NEGATIVE_VALUE). Only
-     applications calling mbedtls_mpi_sub_abs() directly are affected:
-     all calls inside the library were safe since this function is
-     only called with |A| >= |B|. Reported by Guido Vranken in #4042.
diff --git a/ChangeLog.d/net_poll-fd_setsize.txt b/ChangeLog.d/net_poll-fd_setsize.txt
deleted file mode 100644
index e4db8c7..0000000
--- a/ChangeLog.d/net_poll-fd_setsize.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-Security
-   * Fix a stack buffer overflow with mbedtls_net_poll() and
-     mbedtls_net_recv_timeout() when given a file descriptor that is
-     beyond FD_SETSIZE. Reported by FigBug in #4169.
diff --git a/ChangeLog.d/no_ecp_fallback.txt b/ChangeLog.d/no_ecp_fallback.txt
deleted file mode 100644
index f61d311..0000000
--- a/ChangeLog.d/no_ecp_fallback.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-Features
-   * Automatic fallback to a software implementation of ECP when
-     MBEDTLS_ECP_xxx_ALT accelerator hooks are in use can now be turned off
-     through setting the new configuration flag MBEDTLS_ECP_NO_FALLBACK.
diff --git a/ChangeLog.d/programs-ssl-use-after-scope.txt b/ChangeLog.d/programs-ssl-use-after-scope.txt
deleted file mode 100644
index 64bea61..0000000
--- a/ChangeLog.d/programs-ssl-use-after-scope.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-Bugfix
-   * Fix use-after-scope error in programs/ssl/ssl_client2.c and ssl_server2.c
diff --git a/ChangeLog.d/psa-crypto-api-rename-aead-tag-length-macros.txt b/ChangeLog.d/psa-crypto-api-rename-aead-tag-length-macros.txt
deleted file mode 100644
index 58c5e4f..0000000
--- a/ChangeLog.d/psa-crypto-api-rename-aead-tag-length-macros.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-API changes
-   * Renamed the PSA Crypto API AEAD tag length macros to bring them in line
-     with version 1.0.0 of the specification.
-
-New deprecations
-   * PSA_ALG_AEAD_WITH_DEFAULT_TAG_LENGTH and PSA_ALG_AEAD_WITH_TAG_LENGTH
-     have been renamed, and the old names deprecated.
diff --git a/ChangeLog.d/psa-crypto-client.txt b/ChangeLog.d/psa-crypto-client.txt
deleted file mode 100644
index 3070ee9..0000000
--- a/ChangeLog.d/psa-crypto-client.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-Changes
-   * A new library C file psa_crypto_client.c has been created to contain
-     the PSA code needed by a PSA crypto client when the PSA crypto
-     implementation is not included into the library.
diff --git a/ChangeLog.d/psa-crypto-hmac-drbg.txt b/ChangeLog.d/psa-crypto-hmac-drbg.txt
deleted file mode 100644
index 18a0d1b..0000000
--- a/ChangeLog.d/psa-crypto-hmac-drbg.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Features
-   * The PSA crypto subsystem can now use HMAC_DRBG instead of CTR_DRBG.
-     CTR_DRBG is used by default if it is available, but you can override
-     this choice by setting MBEDTLS_PSA_HMAC_DRBG_MD_TYPE at compile time.
-     Fix #3354.
diff --git a/ChangeLog.d/psa-crypto-new-wildcard-policies.txt b/ChangeLog.d/psa-crypto-new-wildcard-policies.txt
deleted file mode 100644
index 56fbbc9..0000000
--- a/ChangeLog.d/psa-crypto-new-wildcard-policies.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Features
-   * In the PSA API, the policy for a MAC or AEAD algorithm can specify a
-     minimum MAC or tag length thanks to the new wildcards
-     PSA_ALG_AT_LEAST_THIS_LENGTH_MAC and
-     PSA_ALG_AEAD_WITH_AT_LEAST_THIS_LENGTH_TAG.
diff --git a/ChangeLog.d/psa-crypto-rename-output-buffer-size-macros.txt b/ChangeLog.d/psa-crypto-rename-output-buffer-size-macros.txt
deleted file mode 100644
index 1e8fb5f..0000000
--- a/ChangeLog.d/psa-crypto-rename-output-buffer-size-macros.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-API changes
-   * Renamed the PSA Crypto API output buffer size macros to bring them in line
-     with version 1.0.0 of the specification.
-
-New deprecations
-   * PSA_KEY_EXPORT_MAX_SIZE, PSA_HASH_SIZE, PSA_MAC_FINAL_SIZE,
-     PSA_BLOCK_CIPHER_BLOCK_SIZE, PSA_MAX_BLOCK_CIPHER_BLOCK_SIZE and
-     PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN have been renamed, and the old names
-     deprecated.
diff --git a/ChangeLog.d/psa_allow_tweaking_library_configuration.txt b/ChangeLog.d/psa_allow_tweaking_library_configuration.txt
deleted file mode 100644
index 78b082c..0000000
--- a/ChangeLog.d/psa_allow_tweaking_library_configuration.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Features
-   * The PSA crypto subsystem can now be configured to use less static RAM by
-     tweaking the setting for the maximum amount of keys simultaneously in RAM.
-     MBEDTLS_PSA_KEY_SLOT_COUNT sets the maximum number of volatile keys that
-     can exist simultaneously. It has a sensible default if not overridden.
diff --git a/ChangeLog.d/psa_close_key_memory_leak_fix.txt b/ChangeLog.d/psa_close_key_memory_leak_fix.txt
deleted file mode 100644
index 91ce174..0000000
--- a/ChangeLog.d/psa_close_key_memory_leak_fix.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-Bugfix
-   * Fix memory leak that occured when calling psa_close_key() on a
-     wrapped key with MBEDTLS_PSA_CRYPTO_SE_C defined.
diff --git a/ChangeLog.d/rsa-mutex.txt b/ChangeLog.d/rsa-mutex.txt
deleted file mode 100644
index 2a477a9..0000000
--- a/ChangeLog.d/rsa-mutex.txt
+++ /dev/null
@@ -1,13 +0,0 @@
-Bugfix
-   * Ensure that calling mbedtls_rsa_free() or mbedtls_entropy_free()
-     twice is safe. This happens for RSA when some Mbed TLS library functions
-     fail. Such a double-free was not safe when MBEDTLS_THREADING_C was
-     enabled on platforms where freeing a mutex twice is not safe.
-   * Fix a resource leak in a bad-arguments case of mbedtls_rsa_gen_key()
-     when MBEDTLS_THREADING_C is enabled on platforms where initializing
-     a mutex allocates resources.
-
-Default behavior changes
-   * In mbedtls_rsa_context objects, the ver field was formerly documented
-     as always 0. It is now reserved for internal purposes and may take
-     different values.
diff --git a/ChangeLog.d/rsa_private-ret.txt b/ChangeLog.d/rsa_private-ret.txt
deleted file mode 100644
index b965cea..0000000
--- a/ChangeLog.d/rsa_private-ret.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-Bugfix
-   * Fix an incorrect error code if an RSA private operation glitched.
diff --git a/doxygen/input/doc_mainpage.h b/doxygen/input/doc_mainpage.h
index 5b51bd5..dcbb705 100644
--- a/doxygen/input/doc_mainpage.h
+++ b/doxygen/input/doc_mainpage.h
@@ -22,7 +22,7 @@
  */
 
 /**
- * @mainpage mbed TLS v2.25.0 source code documentation
+ * @mainpage mbed TLS v2.26.0 source code documentation
  *
  * This documentation describes the internal structure of mbed TLS.  It was
  * automatically generated from specially formatted comment blocks in
diff --git a/doxygen/mbedtls.doxyfile b/doxygen/mbedtls.doxyfile
index dd4237a..27cba6e 100644
--- a/doxygen/mbedtls.doxyfile
+++ b/doxygen/mbedtls.doxyfile
@@ -28,7 +28,7 @@
 # identify the project. Note that if you do not use Doxywizard you need
 # to put quotes around the project name if it contains spaces.
 
-PROJECT_NAME           = "mbed TLS v2.25.0"
+PROJECT_NAME           = "mbed TLS v2.26.0"
 
 # The PROJECT_NUMBER tag can be used to enter a project or revision number.
 # This could be handy for archiving the generated documentation or
diff --git a/include/mbedtls/version.h b/include/mbedtls/version.h
index 10c4316..5b0c70f 100644
--- a/include/mbedtls/version.h
+++ b/include/mbedtls/version.h
@@ -37,7 +37,7 @@
  * Major, Minor, Patchlevel
  */
 #define MBEDTLS_VERSION_MAJOR  2
-#define MBEDTLS_VERSION_MINOR  25
+#define MBEDTLS_VERSION_MINOR  26
 #define MBEDTLS_VERSION_PATCH  0
 
 /**
@@ -45,9 +45,9 @@
  *    MMNNPP00
  *    Major version | Minor version | Patch version
  */
-#define MBEDTLS_VERSION_NUMBER         0x02190000
-#define MBEDTLS_VERSION_STRING         "2.25.0"
-#define MBEDTLS_VERSION_STRING_FULL    "mbed TLS 2.25.0"
+#define MBEDTLS_VERSION_NUMBER         0x021A0000
+#define MBEDTLS_VERSION_STRING         "2.26.0"
+#define MBEDTLS_VERSION_STRING_FULL    "mbed TLS 2.26.0"
 
 #if defined(MBEDTLS_VERSION_C)
 
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 9c252a8..c7542b5 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -196,15 +196,15 @@
 
 if(USE_SHARED_MBEDTLS_LIBRARY)
     add_library(${mbedcrypto_target} SHARED ${src_crypto})
-    set_target_properties(${mbedcrypto_target} PROPERTIES VERSION 2.25.0 SOVERSION 6)
+    set_target_properties(${mbedcrypto_target} PROPERTIES VERSION 2.26.0 SOVERSION 6)
     target_link_libraries(${mbedcrypto_target} PUBLIC ${libs})
 
     add_library(${mbedx509_target} SHARED ${src_x509})
-    set_target_properties(${mbedx509_target} PROPERTIES VERSION 2.25.0 SOVERSION 1)
+    set_target_properties(${mbedx509_target} PROPERTIES VERSION 2.26.0 SOVERSION 1)
     target_link_libraries(${mbedx509_target} PUBLIC ${libs} ${mbedcrypto_target})
 
     add_library(${mbedtls_target} SHARED ${src_tls})
-    set_target_properties(${mbedtls_target} PROPERTIES VERSION 2.25.0 SOVERSION 13)
+    set_target_properties(${mbedtls_target} PROPERTIES VERSION 2.26.0 SOVERSION 13)
     target_link_libraries(${mbedtls_target} PUBLIC ${libs} ${mbedx509_target})
 endif(USE_SHARED_MBEDTLS_LIBRARY)
 
diff --git a/library/base64.c b/library/base64.c
index d39474a..1a05226 100644
--- a/library/base64.c
+++ b/library/base64.c
@@ -66,6 +66,99 @@
 #define BASE64_SIZE_T_MAX   ( (size_t) -1 ) /* SIZE_T_MAX is not standard */
 
 /*
+ * Constant flow conditional assignment to unsigned char
+ */
+static void mbedtls_base64_cond_assign_uchar( unsigned char * dest, const unsigned char * const src,
+                                       unsigned char condition )
+{
+    /* MSVC has a warning about unary minus on unsigned integer types,
+     * but this is well-defined and precisely what we want to do here. */
+#if defined(_MSC_VER)
+#pragma warning( push )
+#pragma warning( disable : 4146 )
+#endif
+
+    /* Generate bitmask from condition, mask will either be 0xFF or 0 */
+    unsigned char mask = ( condition | -condition );
+    mask >>= 7;
+    mask = -mask;
+
+#if defined(_MSC_VER)
+#pragma warning( pop )
+#endif
+
+    *dest = ( ( *src ) & mask ) | ( ( *dest ) & ~mask );
+}
+
+/*
+ * Constant flow conditional assignment to uint_32
+ */
+static void mbedtls_base64_cond_assign_uint32( uint32_t * dest, const uint32_t src,
+                                       uint32_t condition )
+{
+    /* MSVC has a warning about unary minus on unsigned integer types,
+     * but this is well-defined and precisely what we want to do here. */
+#if defined(_MSC_VER)
+#pragma warning( push )
+#pragma warning( disable : 4146 )
+#endif
+
+    /* Generate bitmask from condition, mask will either be 0xFFFFFFFF or 0 */
+    uint32_t mask = ( condition | -condition );
+    mask >>= 31;
+    mask = -mask;
+
+#if defined(_MSC_VER)
+#pragma warning( pop )
+#endif
+
+    *dest = ( src & mask ) | ( ( *dest ) & ~mask );
+}
+
+/*
+ * Constant flow check for equality
+ */
+static unsigned char mbedtls_base64_eq( size_t in_a, size_t in_b )
+{
+    size_t difference = in_a ^ in_b;
+
+    /* MSVC has a warning about unary minus on unsigned integer types,
+     * but this is well-defined and precisely what we want to do here. */
+#if defined(_MSC_VER)
+#pragma warning( push )
+#pragma warning( disable : 4146 )
+#endif
+
+    difference |= -difference;
+
+#if defined(_MSC_VER)
+#pragma warning( pop )
+#endif
+
+    /* cope with the varying size of size_t per platform */
+    difference >>= ( sizeof( difference ) * 8 - 1 );
+
+    return (unsigned char) ( 1 ^ difference );
+}
+
+/*
+ * Constant flow lookup into table.
+ */
+static unsigned char mbedtls_base64_table_lookup( const unsigned char * const table,
+                                                 const size_t table_size, const size_t table_index )
+{
+    size_t i;
+    unsigned char result = 0;
+
+    for( i = 0; i < table_size; ++i )
+    {
+        mbedtls_base64_cond_assign_uchar( &result, &table[i], mbedtls_base64_eq( i, table_index ) );
+    }
+
+    return result;
+}
+
+/*
  * Encode a buffer into base64 format
  */
 int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen,
@@ -105,10 +198,17 @@
         C2 = *src++;
         C3 = *src++;
 
-        *p++ = base64_enc_map[(C1 >> 2) & 0x3F];
-        *p++ = base64_enc_map[(((C1 &  3) << 4) + (C2 >> 4)) & 0x3F];
-        *p++ = base64_enc_map[(((C2 & 15) << 2) + (C3 >> 6)) & 0x3F];
-        *p++ = base64_enc_map[C3 & 0x3F];
+        *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ),
+                                            ( ( C1 >> 2 ) & 0x3F ) );
+
+        *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ),
+                                            ( ( ( ( C1 &  3 ) << 4 ) + ( C2 >> 4 ) ) & 0x3F ) );
+
+        *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ),
+                                            ( ( ( ( C2 & 15 ) << 2 ) + ( C3 >> 6 ) ) & 0x3F ) );
+
+        *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ),
+                                            ( C3 & 0x3F ) );
     }
 
     if( i < slen )
@@ -116,11 +216,15 @@
         C1 = *src++;
         C2 = ( ( i + 1 ) < slen ) ? *src++ : 0;
 
-        *p++ = base64_enc_map[(C1 >> 2) & 0x3F];
-        *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F];
+        *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ),
+                                            ( ( C1 >> 2 ) & 0x3F ) );
+
+        *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ),
+                                            ( ( ( ( C1 & 3 ) << 4 ) + ( C2 >> 4 ) ) & 0x3F ) );
 
         if( ( i + 1 ) < slen )
-             *p++ = base64_enc_map[((C2 & 15) << 2) & 0x3F];
+             *p++ = mbedtls_base64_table_lookup( base64_enc_map, sizeof( base64_enc_map ),
+                                                 ( ( ( C2 & 15 ) << 2 ) & 0x3F ) );
         else *p++ = '=';
 
         *p++ = '=';
@@ -141,6 +245,7 @@
     size_t i, n;
     uint32_t j, x;
     unsigned char *p;
+    unsigned char dec_map_lookup;
 
     /* First pass: check for validity and get output length */
     for( i = n = j = 0; i < slen; i++ )
@@ -171,10 +276,12 @@
         if( src[i] == '=' && ++j > 2 )
             return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
 
-        if( src[i] > 127 || base64_dec_map[src[i]] == 127 )
+        dec_map_lookup = mbedtls_base64_table_lookup( base64_dec_map, sizeof( base64_dec_map ), src[i] );
+
+        if( src[i] > 127 || dec_map_lookup == 127 )
             return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
 
-        if( base64_dec_map[src[i]] < 64 && j != 0 )
+        if( dec_map_lookup < 64 && j != 0 )
             return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
 
         n++;
@@ -204,8 +311,10 @@
         if( *src == '\r' || *src == '\n' || *src == ' ' )
             continue;
 
-        j -= ( base64_dec_map[*src] == 64 );
-        x  = ( x << 6 ) | ( base64_dec_map[*src] & 0x3F );
+        dec_map_lookup = mbedtls_base64_table_lookup( base64_dec_map, sizeof( base64_dec_map ), *src );
+
+        mbedtls_base64_cond_assign_uint32( &j, j - 1, mbedtls_base64_eq( dec_map_lookup, 64 ) );
+        x  = ( x << 6 ) | ( dec_map_lookup & 0x3F );
 
         if( ++n == 4 )
         {
diff --git a/tests/suites/test_suite_base64.data b/tests/suites/test_suite_base64.data
index da99ffa..3a892f4 100644
--- a/tests/suites/test_suite_base64.data
+++ b/tests/suites/test_suite_base64.data
@@ -151,6 +151,20 @@
 Base64 encode hex #4
 base64_encode_hex:"01020304050607":"AQIDBAUGBw==":13:0
 
+# Rotate the bytes around so that they end up at each offset modulo 3 in
+# successive test cases.
+Base64 encode hex all valid input bytes #0
+base64_encode_hex:"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f404142434445464748494a4b4c4d4e4f505152535455565758595a5b5c5d5e5f606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9aaabacadaeafb0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff":"AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS4vMDEyMzQ1Njc4OTo7PD0+P0BBQkNERUZHSElKS0xNTk9QUVJTVFVWV1hZWltcXV5fYGFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6e3x9fn+AgYKDhIWGh4iJiouMjY6PkJGSk5SVlpeYmZqbnJ2en6ChoqOkpaanqKmqq6ytrq+wsbKztLW2t7i5uru8vb6/wMHCw8TFxsfIycrLzM3Oz9DR0tPU1dbX2Nna29zd3t/g4eLj5OXm5+jp6uvs7e7v8PHy8/T19vf4+fr7/P3+/w==":345:0
+
+Base64 encode hex all valid input bytes #1
+base64_encode_hex:"0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f404142434445464748494a4b4c4d4e4f505152535455565758595a5b5c5d5e5f606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9aaabacadaeafb0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff00":"AQIDBAUGBwgJCgsMDQ4PEBESExQVFhcYGRobHB0eHyAhIiMkJSYnKCkqKywtLi8wMTIzNDU2Nzg5Ojs8PT4/QEFCQ0RFRkdISUpLTE1OT1BRUlNUVVZXWFlaW1xdXl9gYWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXp7fH1+f4CBgoOEhYaHiImKi4yNjo+QkZKTlJWWl5iZmpucnZ6foKGio6SlpqeoqaqrrK2ur7CxsrO0tba3uLm6u7y9vr/AwcLDxMXGx8jJysvMzc7P0NHS09TV1tfY2drb3N3e3+Dh4uPk5ebn6Onq6+zt7u/w8fLz9PX29/j5+vv8/f7/AA==":345:0
+
+Base64 encode hex all valid input bytes #2
+base64_encode_hex:"02030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f404142434445464748494a4b4c4d4e4f505152535455565758595a5b5c5d5e5f606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9aaabacadaeafb0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff0001":"AgMEBQYHCAkKCwwNDg8QERITFBUWFxgZGhscHR4fICEiIyQlJicoKSorLC0uLzAxMjM0NTY3ODk6Ozw9Pj9AQUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVpbXF1eX2BhYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ent8fX5/gIGCg4SFhoeIiYqLjI2Oj5CRkpOUlZaXmJmam5ydnp+goaKjpKWmp6ipqqusra6vsLGys7S1tre4ubq7vL2+v8DBwsPExcbHyMnKy8zNzs/Q0dLT1NXW19jZ2tvc3d7f4OHi4+Tl5ufo6err7O3u7/Dx8vP09fb3+Pn6+/z9/v8AAQ==":345:0
+
+Base64 encode all valid output characters at all offsets
+base64_encode_hex:"00108310518720928b30d38f41149351559761969b71d79f8218a39259a7a29aabb2dbafc31cb3d35db7e39ebbf3dfbff800420c41461c824a2cc34e3d04524d45565d865a6dc75e7e08628e49669e8a6aaecb6ebf0c72cf4d76df8e7aefcf7effe00108310518720928b30d38f41149351559761969b71d79f8218a39259a7a29aabb2dbafc31cb3d35db7e39ebbf3dfbff800420c41461c824a2cc34e3d04524d45565d865a6dc75e7e08628e49669e8a6aaecb6ebf0c72cf4d76df8e7aefcf7efd0":"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/+ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/+ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/+ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/Q":261:0
+
 Base64 decode hex #1
 base64_decode_hex:"AQIDBAUGBwgJ":"010203040506070809":9:0
 
@@ -166,6 +180,9 @@
 Base64 decode hex #5 (buffer too small)
 base64_decode_hex:"AQIDBAUGBw==":"01020304050607":6:MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL
 
+Base64 decode all valid input characters at all offsets
+base64_decode_hex:"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/+ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/+ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/+ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/Q":"00108310518720928b30d38f41149351559761969b71d79f8218a39259a7a29aabb2dbafc31cb3d35db7e39ebbf3dfbff800420c41461c824a2cc34e3d04524d45565d865a6dc75e7e08628e49669e8a6aaecb6ebf0c72cf4d76df8e7aefcf7effe00108310518720928b30d38f41149351559761969b71d79f8218a39259a7a29aabb2dbafc31cb3d35db7e39ebbf3dfbff800420c41461c824a2cc34e3d04524d45565d865a6dc75e7e08628e49669e8a6aaecb6ebf0c72cf4d76df8e7aefcf7efd0":195:0
+
 Base64 Selftest
 depends_on:MBEDTLS_SELF_TEST
 base64_selftest:
diff --git a/tests/suites/test_suite_base64.function b/tests/suites/test_suite_base64.function
index dc6ec15..be9b6e8 100644
--- a/tests/suites/test_suite_base64.function
+++ b/tests/suites/test_suite_base64.function
@@ -1,5 +1,6 @@
 /* BEGIN_HEADER */
 #include "mbedtls/base64.h"
+#include <test/constant_flow.h>
 /* END_HEADER */
 
 /* BEGIN_DEPENDENCIES
@@ -13,13 +14,22 @@
 {
     unsigned char src_str[1000];
     unsigned char dst_str[1000];
-    size_t len;
+    size_t len, src_len;
 
     memset(src_str, 0x00, 1000);
     memset(dst_str, 0x00, 1000);
 
     strncpy( (char *) src_str, src_string, sizeof(src_str) - 1 );
-    TEST_ASSERT( mbedtls_base64_encode( dst_str, dst_buf_size, &len, src_str, strlen( (char *) src_str ) ) == result );
+    src_len = strlen( (char *) src_str );
+
+    TEST_CF_SECRET( src_str, sizeof( src_str ) );
+    TEST_ASSERT( mbedtls_base64_encode( dst_str, dst_buf_size, &len, src_str, src_len) == result );
+    TEST_CF_PUBLIC( src_str, sizeof( src_str ) );
+
+    /* dest_str will have had tainted data copied to it, prevent the TEST_ASSERT below from triggering
+       CF failures by unmarking it. */
+    TEST_CF_PUBLIC( dst_str, len );
+
     if( result == 0 )
     {
         TEST_ASSERT( strcmp( (char *) dst_str, dst_string ) == 0 );
@@ -57,7 +67,14 @@
 
     res = mbedtls_test_zero_alloc( dst_buf_size );
 
+    TEST_CF_SECRET( src->x, src->len );
     TEST_ASSERT( mbedtls_base64_encode( res, dst_buf_size, &len, src->x, src->len ) == result );
+    TEST_CF_PUBLIC( src->x, src->len );
+
+    /* res will have had tainted data copied to it, prevent the TEST_ASSERT below from triggering
+       CF failures by unmarking it. */
+    TEST_CF_PUBLIC( res, len );
+
     if( result == 0 )
     {
         TEST_ASSERT( len == strlen( dst ) );
diff --git a/tests/suites/test_suite_version.data b/tests/suites/test_suite_version.data
index 2b01227..e4da3d4 100644
--- a/tests/suites/test_suite_version.data
+++ b/tests/suites/test_suite_version.data
@@ -1,8 +1,8 @@
 Check compiletime library version
-check_compiletime_version:"2.25.0"
+check_compiletime_version:"2.26.0"
 
 Check runtime library version
-check_runtime_version:"2.25.0"
+check_runtime_version:"2.26.0"
 
 Check for MBEDTLS_VERSION_C
 check_feature:"MBEDTLS_VERSION_C":0