# CVE-2026-77118: graphicsmagick: A heap out-of-bounds write exists in the Photo CD (PCD) decoder of GraphicsMagick

CVE-2026-77118 is fixed in 11 products on 1 platform, first by ALAS2023-2026-1960, released July 20, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-77118
- Priority: High
- CVSS: n/a (important)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 20, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | GraphicsMagick amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-c++ amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-c++-debuginfo amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-c++-devel amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-debuginfo amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-debugsource amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-devel amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-doc amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-perl amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | GraphicsMagick-perl-debuginfo amzn 2023 | 1.3.45-1.amzn2023.0.3 | [ALAS2023-2026-1960](https://patchblox.com/security/data/fix/linux/alas2023-2026-1960.md) | Jul 20, 2026 |
| Linux | graphicsmagick Debian 14 | 1.4+really1.3.48-1 | [DEBIAN-CVE-2026-77118](https://patchblox.com/security/data/fix/linux/debian-cve-2026-77118.md) | Aug 20, 2026 |

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Data as of 2026-11-10T01:44:33Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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