---
id: CVE-2026-77118
title: >-
  A heap out-of-bounds write exists in the Photo CD (PCD) decoder of
  GraphicsMagick
summary: >-
  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…
severity: none
cwe:
  - CWE-787
published: '2026-08-20'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T15:52:04.827'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77118'
references:
  - url: >-
      https://foss.heptapod.net/graphicsmagick/graphicsmagick/-/commit/937cdd9920bd96
    label: 22e2d327-25fe-45d7-9f0c-dcd23b7108df
  - url: >-
      https://foss.heptapod.net/graphicsmagick/graphicsmagick/-/raw/GraphicsMagick-1_3_48/ChangeLog
    label: 22e2d327-25fe-45d7-9f0c-dcd23b7108df
tags:
  - nvd
epss: 0.00171
epssPercentile: 0.05833
ingestedAt: '2026-09-09T16:14:05.514Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.