From 9e80713e5132a3bd26702ee0a833306f7e801469 Mon Sep 17 00:00:00 2001
From: Cristy <urban-warrior@imagemagick.org>
Date: Fri, 23 Feb 2018 05:15:02 -0500
Subject: [PATCH] https://github.com/ImageMagick/ImageMagick/issues/998

---
 coders/webp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/coders/webp.c b/coders/webp.c
index 17e071b12..fffccd77e 100644
--- a/coders/webp.c
+++ b/coders/webp.c
@@ -187,7 +187,7 @@ static MagickBooleanType IsWEBPImageLossless(const unsigned char *stream,
     Read extended header.
   */
   offset=RIFF_HEADER_SIZE+TAG_SIZE+CHUNK_SIZE_BYTES+VP8X_CHUNK_SIZE;
-  while (offset <= (ssize_t) length)
+  while (offset <= (ssize_t) (length-TAG_SIZE))
   {
     uint32_t
       chunk_size,
-- 
2.40.0