CVE-2026-77118

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.

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Produits concernés

• GraphicsMagick Group GraphicsMagick
• Debian graphicsmagick
• Fedora Project GraphicsMagick

Scores CVSS

Faiblesses (CWE)

• CWE-787

Références

• https://foss.heptapod.net/graphicsmagick/graphicsmagick/-/commit/937cdd9920bd96
• https://foss.heptapod.net/graphicsmagick/graphicsmagick/-/raw/GraphicsMagick-1_3_48/ChangeLog

Ailleurs

• NVD
• CVE.org
• CIRCL Vulnerability-Lookup
• CERT-FR
• GitHub Advisories