CVE-2026-106117 ImageSharp: CCITT fax decompression (T4/Modified Huffman): unbounded WriteBits overflows strip buffer — heap OOB write in SixLabors.ImageSharp
Attackers can cause heap overflow and potential code execution by crafting malicious TIFF images processed by the ImageSharp library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-106117?
CVE-2026-106117 is a high-severity memory corruption vulnerability in SixLabors ImageSharp, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
ImageSharp is a 2D graphics library. From 3.0.0 until 4.1.1, decoding a strip TIFF using CCITT Group 3 or Modified Huffman compression can pass attacker-expanded runs to BitWriterUtils.WriteBits without first checking the current row width. T4TiffCompression.WritePixelRun can accumulate oversized makeup-code runs, and ModifiedHuffmanTiffCompression.Decompress validates the width only after writing. The unchecked writes can overflow the strip buffer, corrupt heap memory, and terminate the process. This strip-path vulnerability is distinct from the tiled decompressor-width mismatch. This issue is fixed in version 4.1.1.
Weakness: CWE-787
Which versions are affected by CVE-2026-106117?
4 open source packages ship an affected version, including ImageSharp. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
ImageSharp NuGet | From 3.0.0 | 3.2.0 |
ImageSharp NuGet | From 3.0.0 | 3.2.0 |
ImageSharp NuGet | From 4.0.0 | 4.1.1 |
ImageSharp NuGet | From 4.0.0 | 4.1.1 |
Products include Sixlabors Imagesharp.
How do I fix CVE-2026-106117?
Upgrade ImageSharp to a fixed version for your release line: 3.2.0 or 4.1.1.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-106117 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-106117 exists.
Other vulnerabilities in SixLabors ImageSharp
- CVE-2026-106110 ImageSharp: TIFF CCITT T4 encoder can write past its compressed output buffer
- CVE-2026-106112 ImageSharp: ICC LUT16 output channel count can write beyond Vector4
- CVE-2026-106113 ImageSharp: HistogramEqualization uses an unvalidated luminance as an unchecked histogram index
- CVE-2026-106115 ImageSharp: TIFF CCITT T6 encoder writes beyond an undersized output buffer
- CVE-2025-27598 Out-of-bounds Write in SixLabors ImageSharp
Sources
Also known as ECHO-58f4-65d8-34a6, GHSA-jj3q-cwqj-842r.