What’s Vulnerable › Vulnerabilities

CVE-2026-106115: ImageSharp: TIFF CCITT T6 encoder writes beyond an undersized output buffer

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-10-06 · updated 2026-10-24
• Weakness: CWE-787

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: from 2.1.0 before 3.2.0; from 4.0.0 before 4.1.2 — fixed in 3.2.0, 4.1.2

How to fix

Upgrade to a fixed version: SixLabors ImageSharp 3.2.0, 4.1.2. Check the vendor advisory for mitigations.

References

• https://github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc81e706914ac16a95
• https://github.com/SixLabors/ImageSharp/pull/3187
• https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2
• https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-jjfr-hcj7-qf5w
• https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-jjfr-hcj7-qf5w

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