commit f5b7267aed3665ef025c13823e454170d031c106
Author: Eric S. Raymond <esr@thyrsus.com>
Date:   Wed Mar 4 18:49:49 2026 -0500

    Avoid potentuial double-free on weird images.

CVE: CVE-2026-23868
Upstream: https://sourceforge.net/p/giflib/code/ci/f5b7267aed3665ef025c13823e454170d031c106
Signed-off-by: Thomas Perale <thomas.perale@mind.be>

diff --git a/gifalloc.c b/gifalloc.c
index 01a845d..ff70cb0 100644
--- a/gifalloc.c
+++ b/gifalloc.c
@@ -349,6 +349,14 @@ SavedImage *GifMakeSavedImage(GifFileType *GifFile,
 			 * aliasing problems.
 			 */
 
+			/* Null out aliased pointers before any allocations
+			 * so that FreeLastSavedImage won't free CopyFrom's
+			 * data if an allocation fails partway through. */
+			sp->ImageDesc.ColorMap = NULL;
+			sp->RasterBits = NULL;
+			sp->ExtensionBlocks = NULL;
+			sp->ExtensionBlockCount = 0;
+ 
 			/* first, the local color map */
 			if (CopyFrom->ImageDesc.ColorMap != NULL) {
 				sp->ImageDesc.ColorMap = GifMakeMapObject(