diff --git a/wolfcrypt/src/aes.c b/wolfcrypt/src/aes.c
index adbe1b1b0..beeae72a6 100644
--- a/wolfcrypt/src/aes.c
+++ b/wolfcrypt/src/aes.c
@@ -2306,6 +2306,8 @@ static void wc_AesDecrypt(Aes* aes, const byte* inBlock, byte* outBlock)
             aes->use_aesni = 1;
             if (iv)
                 XMEMCPY(aes->reg, iv, AES_BLOCK_SIZE);
+            else
+                XMEMSET(aes->reg, 0, AES_BLOCK_SIZE);
             if (dir == AES_ENCRYPTION)
                 return AES_set_encrypt_key(userKey, keylen * 8, aes);
         #ifdef HAVE_AES_DECRYPT