diff --git a/crypto/mem.c b/crypto/mem.c
index d3b2112..15d3436 100644
--- a/crypto/mem.c
+++ b/crypto/mem.c
@@ -180,11 +180,17 @@
 
   size_t size = *(size_t *)ptr;
   OPENSSL_cleanse(ptr, size + OPENSSL_MALLOC_PREFIX);
+
+// ASan knows to intercept malloc and free, but not sdallocx.
+#if defined(OPENSSL_ASAN)
+  free(ptr);
+#else
   if (sdallocx) {
     sdallocx(ptr, size + OPENSSL_MALLOC_PREFIX, 0 /* flags */);
   } else {
     free(ptr);
   }
+#endif
 }
 
 void *OPENSSL_realloc(void *orig_ptr, size_t new_size) {