Quick answers
- Is CVE-2026-77118 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-77118 being exploited in the wild.
- How severe is CVE-2026-77118?
- Informational severity, with a CVSS score of 7.5, published 20 August 2026.
- Which products and versions are affected?
- Graphicsmagick <UNKNOWN>.
- Is there a fix for CVE-2026-77118?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-77118 attacked?
- It is attacked over the network or with local access.
- Am I affected by CVE-2026-77118?
- Check whether you run Graphicsmagick at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A heap out-of-bounds write vulnerability exists in the Photo CD decoder (coders/pcd.c), specifically in the DecodeImage() Huffman delta loop. The vulnerability occurs because the output pointer (q) is incremented after every decoded delta without validation against buffer boundaries; pointer repositioning only happens at sync markers. A crafted PCD file positioning the pointer near buffer end, followed by a long run-length sequence with no intervening sync markers, allows the pointer to advance past the allocated luma/chroma plane buffers and write arbitrary data to adjacent heap memory. Attack vector is network or local (via file processing); no authentication is required. An attacker can corrupt heap memory, trigger crash (DoS), or potentially achieve code execution depending on heap layout and exploitation conditions. Patch status is unknown from the advisory text.
Affected products
- GraphicsMagick GraphicsMagick <UNKNOWN>
Timeline
- 2026-08-20: disclosed