# CVE-2026-106115: ImageSharp TIFF CCITT Group 4 encoder buffer overflow

Source: https://junglewise.ai/threats/cve-2026-106115-imagesharp-is-a-2d-graphics-library-from-2-1-0-until-4-1-2-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-06. Updated: 2026-10-06  
License: CC BY 4.0 with a link back

CVE-2026-106115 · Severity: high · CVSS 7.5 · Published 2026-10-06

ImageSharp is a graphics library used to process and manipulate digital images. A flaw in the TIFF CCITT Group 4 compression encoder can write beyond allocated memory when re-encoding maliciously crafted image files, causing the application to crash or potentially allowing an attacker to corrupt memory. An attacker could exploit this by providing a specially crafted TIFF image.

Technologies: [SixLabors.ImageSharp (NuGet)](https://junglewise.ai/threats/technologies/sixlabors-imagesharp), [SixLabors ImageSharp](https://junglewise.ai/threats/technologies/imagesharp). Vendors: [NuGet](https://junglewise.ai/threats/vendors/nuget), [SixLabors](https://junglewise.ai/threats/vendors/sixlabors).

## Quick answers

**Is CVE-2026-106115 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-106115 being exploited in the wild.

**How severe is CVE-2026-106115?** High severity, with a CVSS score of 7.5, published 6 October 2026.

**Which products and versions are affected?** SixLabors.ImageSharp (NuGet) >= 2.1.0, <= 4.1.1, ECOSYSTEM:introduced=2.1.0,fixed=4.1.2; SixLabors ImageSharp 2.1.0 to 4.1.1.

**Is there a fix for CVE-2026-106115?** Yes. SixLabors.ImageSharp (NuGet): upgrade to 4.1.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-106115 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-106115?** Check whether you run SixLabors.ImageSharp (NuGet) or SixLabors ImageSharp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- SixLabors.ImageSharp (NuGet): upgrade to 4.1.2 or later

  ```sh
  dotnet add package SixLabors.ImageSharp --version 4.1.2
  ```


## Technical details

The TIFF CCITT Group 4 encoder in ImageSharp allocates Width × rowsPerStrip bytes, but the T6BitCompressor.CompressStrip method can emit encoded data exceeding this capacity, including two 12-bit end-of-facsimile-block codes. TiffCcittCompressor.WriteCode performs unchecked writes, resulting in out-of-bounds memory writes. A decode-and-re-encode flow can inherit CCITT Group 4 compression settings from attacker-supplied TIFF input, triggering the vulnerability.

## Affected products

- SixLabors ImageSharp 2.1.0 to 4.1.1

## Identifiers

- CVE-2026-106115
- GHSA-jjfr-hcj7-qf5w

## Timeline

- 2026-10-06: disclosed
- 2026-09-12: patched

## References

- [https://github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc81e706914ac16a95](https://github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc81e706914ac16a95)
- [https://github.com/SixLabors/ImageSharp/pull/3187](https://github.com/SixLabors/ImageSharp/pull/3187)

## Related threats

- [SixLabors ImageSharp TIFF heap overflow in tiled CCITT decompression](https://junglewise.ai/threats/cve-2026-106118-imagesharp-is-a-2d-graphics-library-from-3-0-0-until-4-1-1-tiled)
- [ImageSharp buffer overflow in CCITT TIFF decompression](https://junglewise.ai/threats/cve-2026-106117-imagesharp-is-a-2d-graphics-library-from-3-0-0-until-4-1-1)
- [SixLabors ImageSharp denial of service in EXIF BigTIFF parser](https://junglewise.ai/threats/cve-2026-106116-imagesharp-is-a-2d-graphics-library-from-2-0-0-until-4-1-2)
- [SixLabors ImageSharp ICC CLUT buffer over-allocation](https://junglewise.ai/threats/cve-2026-106114-imagesharp-is-a-2d-graphics-library-from-1-0-0-beta0001-until-4)
- [ImageSharp out-of-range access in histogram equalization](https://junglewise.ai/threats/cve-2026-106113-imagesharp-is-a-2d-graphics-library-from-2-0-0-until-4-1-2)