diff --git a/crypto/hkdf/hkdf.c b/crypto/hkdf/hkdf.c
index 5412b68..d80834d 100644
--- a/crypto/hkdf/hkdf.c
+++ b/crypto/hkdf/hkdf.c
@@ -102,6 +102,7 @@
   ret = 1;
 
 out:
+  HMAC_CTX_cleanup(&hmac);
   if (ret != 1) {
     OPENSSL_PUT_ERROR(HKDF, ERR_R_HMAC_LIB);
   }