From 8f300af691efb83b6f7db76bf5f6fe66cbce6f02 Mon Sep 17 00:00:00 2001
From: Eric Soroos <eric-github@soroos.net>
Date: Sun, 8 Aug 2021 15:01:19 +0200
Subject: [PATCH] Actually check the framesize in FliDecode.

---
 src/libImaging/FliDecode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/libImaging/FliDecode.c b/src/libImaging/FliDecode.c
index 3a6030703..f56432034 100644
--- a/src/libImaging/FliDecode.c
+++ b/src/libImaging/FliDecode.c
@@ -46,7 +46,8 @@ ImagingFliDecode(Imaging im, ImagingCodecState state, UINT8 *buf, Py_ssize_t byt
     ptr = buf;
 
     framesize = I32(ptr);
-    if (framesize < I32(ptr)) {
+    // there can be one pad byte in the framesize
+    if (bytes + (bytes % 2) < framesize) {
         return 0;
     }