diff --git a/crypto/aes/aes_cfb.c b/crypto/aes/aes_cfb.c
index 5ee3e7277b..064b0d8b13 100644
--- a/crypto/aes/aes_cfb.c
+++ b/crypto/aes/aes_cfb.c
@@ -190,7 +190,7 @@ void AES_cfbr_encrypt_block(const unsigned char *in,unsigned char *out,
 			    unsigned char *ivec,const int enc)
     {
     int n,rem,num;
-    unsigned char ovec[AES_BLOCK_SIZE*2];
+    unsigned char ovec[AES_BLOCK_SIZE*2 + 1];  /* +1 because we dererefence (but don't use) one byte off the end */
 
     if (nbits<=0 || nbits>128) return;