AIKIDO-2026-983562
SixLabors.ImageSharp is vulnerable to Out-of-bounds Write
75
High Risk
This Affects:
SixLabors.ImageSharpTL;DR
The TIFF decoder's CCITT fax decompressors write decoded run-length codes without validating them against the output buffer size. Decoding a crafted TIFF that uses T4 (Group 3 1D) or Modified Huffman compression lets oversized makeup codes accumulate into runs that write past the strip buffer. This out-of-bounds heap write crashes the process and can corrupt heap memory, and it is reachable from Image.Load on untrusted input. The fix adds explicit bounds checks before writing decoded runs and standardizes overrun error handling.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you decode untrusted TIFF images that use CCITT/fax (Group 3 or Modified Huffman) compression.
Background info
SixLabors.ImageSharp is vulnerable to Out-of-bounds Write in versions 3.0.0 - 4.1.0.
How to fix this
Upgrade the SixLabors.ImageSharp library to the patch version.
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SOC 2Compliant
ISO 27001Compliant