Bug 2521293

Summary:	CVE-2026-77118 GraphicsMagick: GraphicsMagick: Arbitrary code execution via crafted PCD file [fedora-all]
Product:	[Fedora] Fedora	Reporter:	Vladimir Vasilev <vvasilev>
Component:	GraphicsMagick	Assignee:	Andreas Thienemann <andreas>
Status:	NEW ---	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	andreas, davide, michel, ngompa13
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["64abc823-3b93-41ce-9244-0594f75e653d"]}
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2520299

Description Vladimir Vasilev 2026-08-22 12:01:17 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A heap out-of-bounds write exists in the Photo CD (PCD) decoder of GraphicsMagick. In DecodeImage() (coders/pcd.c), the Huffman delta loop advances its output pointer with q++ after every decoded delta and never checks it against the end of the heap-allocated luma/chroma plane buffers. The pointer is repositioned only when a sync marker introduces a new plane/row; between sync markers the run length is bounded solely by the input.



A crafted PCD file that positions the pointer near the end of a plane and then supplies a long run of deltas with no intervening sync therefore walks the pointer past the end of the allocation and writes through it. Processing an untrusted PCD file — for example with gm convert or gm identify, or through any application linked against libGraphicsMagick — can corrupt heap memory beyond the buffers.