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.
History

Thu, 20 Aug 2026 13:15:00 +0000

Type Values Removed Values Added
Description 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.
Title Out-of-bounds write in GraphicsMagick PCD decoder
First Time appeared Debian
Debian debian Linux
Fedoraproject
Fedoraproject extra Packages For Enterprise Linux
Graphicsmagick
Graphicsmagick graphicsmagick
Weaknesses CWE-787
CPEs cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:a:graphicsmagick:graphicsmagick:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:12:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:13:*:*:*:*:*:*:*
Vendors & Products Debian
Debian debian Linux
Fedoraproject
Fedoraproject extra Packages For Enterprise Linux
Graphicsmagick
Graphicsmagick graphicsmagick
References
Metrics cvssV4_0

{'score': 8.4, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: seal

Published: 2026-08-20T12:42:42.952Z

Updated: 2026-08-20T12:56:01.246Z

Reserved: 2026-08-20T12:40:51.495Z

Link: CVE-2026-77118

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-20T13:19:07.077

Modified: 2026-08-20T13:19:07.077

Link: CVE-2026-77118

cve-icon Redhat

No data.