diff --git a/crypto/camellia/cmll_cfb.c b/crypto/camellia/cmll_cfb.c
index af0f9f49a..1b02bebd5 100644
--- a/crypto/camellia/cmll_cfb.c
+++ b/crypto/camellia/cmll_cfb.c
@@ -173,7 +173,7 @@ void Camellia_cfbr_encrypt_block(const unsigned char *in,unsigned char *out,
 	unsigned char *ivec,const int enc)
 	{
 	int n,rem,num;
-	unsigned char ovec[CAMELLIA_BLOCK_SIZE*2];
+	unsigned char ovec[CAMELLIA_BLOCK_SIZE*2 + 1];  /* +1 because we dereference (but don't use) one byte beyond the end */
 
 	if (nbits<=0 || nbits>128) return;