ImageSharp is a 2D graphics library. From 2.1.0 until 4.1.2, the TIFF CCITT Group 4 encoder allocates Width times rowsPerStrip bytes even though T6BitCompressor.CompressStrip can emit encoded row data and two 12-bit end-of-facsimile-block codes beyond that capacity. TiffCcittCompressor.WriteCode performs unchecked writes, and a decode-and-re-encode flow can inherit TiffCompression.CcittGroup4Fax and one-bit metadata from attacker-supplied input. The resulting out-of-bounds writes can corrupt memory and terminate the process. This issue is fixed in version 4.1.2.
Fix
Patch, vendor advisory and mitigation references on NVD 4
- https://github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc81e706914ac16a95 Patch
- https://github.com/SixLabors/ImageSharp/pull/3187 Issue Tracking, Patch
- https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-jjfr-hcj7-qf5w Exploit, Vendor Advisory
- https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-jjfr-hcj7-qf5w Exploit, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 3
- Cpes+1 CPE criteria (now 1)NVD modified 2026-10-24 01:27
- StatusUndergoing Analysis → AnalyzedNVD modified 2026-10-24 01:27
- First seenCVSS 7.5NVD modified 2026-10-09 02:16
Affected (CPE criteria) 1
cpe:2.3:a:sixlabors:imagesharp:*:*:*:*:*:*:*:*
References 5
- https://github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc81e706914ac16a95 Patch
- https://github.com/SixLabors/ImageSharp/pull/3187 Issue Tracking, Patch
- https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2 Release Notes
- https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-jjfr-hcj7-qf5w Exploit, Vendor Advisory
- https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-jjfr-hcj7-qf5w Exploit, Vendor Advisory