diff --git a/ChangeLog b/ChangeLog
index 3ae00de22..0c85b35b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2015-01-20  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/disk/AFSplitter.c (AF_merge): Check that mdlen is not 0.
+
 2015-01-20  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/commands/i386/pc/play.c (grub_cmd_play): Avoid
diff --git a/grub-core/disk/AFSplitter.c b/grub-core/disk/AFSplitter.c
index d76a1c447..7e1bd5748 100644
--- a/grub-core/disk/AFSplitter.c
+++ b/grub-core/disk/AFSplitter.c
@@ -76,7 +76,7 @@ AF_merge (const gcry_md_spec_t * hash, grub_uint8_t * src, grub_uint8_t * dst,
   if (bufblock == NULL)
     return GPG_ERR_OUT_OF_MEMORY;
 
-  if (hash->mdlen > GRUB_CRYPTO_MAX_MDLEN)
+  if (hash->mdlen > GRUB_CRYPTO_MAX_MDLEN || hash->mdlen == 0)
     return GPG_ERR_INV_ARG;
 
   grub_memset (bufblock, 0, blocksize);