Description
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.
Affected products
sixlabors: imagesharp
References5
- github.com/SixLabors/ImageSharp/security/advisories/GHSA-jjfr-h… ExploitVendor Advisory
- github.com/SixLabors/ImageSharp/security/advisories/GHSA-jjfr-h… ExploitVendor Advisory
- github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc… Patch
- github.com/SixLabors/ImageSharp/pull/3187 Issue TrackingPatch
- github.com/SixLabors/ImageSharp/releases/tag/v4.1.2 Release Notes
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 33 · as of 10 November 2026
- CWE
- CWE-787
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