Out-of-bounds write in GraphicsMagick PCD decoder (CVE-2026-77118) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-77118

Out-of-bounds write in GraphicsMagick PCD decoder

Answer in brief

CVE-2026-77118 records a Unknown severity vulnerability in Out-of-bounds write in GraphicsMagick PCD decoder. The current sources do not mark it as known exploited. The current feed maps Debian/graphicsmagick (generic), GraphicsMagick Group/GraphicsMagick (generic), Fedora Project/GraphicsMagick (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 20, 2026Updated Aug 20, 2026Source checked Aug 20, 2026First seen by HOL Aug 20, 2026Material review Aug 20, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Debian/graphicsmagick (generic), GraphicsMagick Group/GraphicsMagick (generic), Fedora Project/GraphicsMagick (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Debian/graphicsmagickgeneric	>=0 <1.4+really1.3.48-1	1.4+really1.3.48-1
GraphicsMagick Group/GraphicsMagickgeneric	>=1.0.0 <1.3.48	1.3.48
Fedora Project/GraphicsMagickgeneric	>=0 <1.3.48	1.3.48

Recommended response

Check inventory. Check lockfiles and deployed manifests for Debian/graphicsmagick, GraphicsMagick Group/GraphicsMagick, Fedora Project/GraphicsMagick.
Review the reported fix. Update Debian/graphicsmagick to 1.4+really1.3.48-1; GraphicsMagick Group/GraphicsMagick to 1.3.48; Fedora Project/GraphicsMagick to 1.3.48 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 20, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 20, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 20, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.