# CVE-2026-106115: ImageSharp: TIFF CCITT T6 encoder writes beyond an undersized output buffer

> Attacker-supplied TIFF images can trigger out-of-bounds writes in ImageSharp, causing memory corruption and potential code execution or crashes.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 9 Oct 2026
- **Also known as:** ECHO-58f6-50c4-c97e, GHSA-jjfr-hcj7-qf5w

## What is CVE-2026-106115?

CVE-2026-106115 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 2.1.0 until 4.1.2, the TIFF CCITT Group 4 encoder allocates Width times rowsPerStrip bytes even though T6BitCompressor.CompressStrip can emit encoded row data and two 12-bit end-of-facsimile-block codes beyond that capacity. TiffCcittCompressor.WriteCode performs unchecked writes, and a decode-and-re-encode flow can inherit TiffCompression.CcittGroup4Fax and one-bit metadata from attacker-supplied input. The resulting out-of-bounds writes can corrupt memory and terminate the process. This issue is fixed in version 4.1.2.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-106115?

4 open source packages ship an affected version, including SixLabors.ImageSharp. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `SixLabors.ImageSharp` | NuGet | From 2.1.0 | 3.2.0 |
| `SixLabors.ImageSharp` | NuGet | From 2.1.0 | 3.2.0 |
| `SixLabors.ImageSharp` | NuGet | From 4.0.0 | 4.1.2 |
| `SixLabors.ImageSharp` | NuGet | From 4.0.0 | 4.1.2 |

Products: Sixlabors Imagesharp.

## How do I fix CVE-2026-106115?

Upgrade SixLabors.ImageSharp to a fixed version for your release line: 3.2.0 or 4.1.2.

## Is CVE-2026-106115 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-106115 exists.

## Other vulnerabilities in SixLabors ImageSharp

- [CVE-2026-106110](https://insights.sbomify.com/CVE-2026-106110/): ImageSharp: TIFF CCITT T4 encoder can write past its compressed output buffer (high 7.5)
- [CVE-2026-106112](https://insights.sbomify.com/CVE-2026-106112/): ImageSharp: ICC LUT16 output channel count can write beyond Vector4 (high 7.5)
- [CVE-2026-106113](https://insights.sbomify.com/CVE-2026-106113/): ImageSharp: HistogramEqualization uses an unvalidated luminance as an unchecked histogram index (high 7.5)
- [CVE-2026-106117](https://insights.sbomify.com/CVE-2026-106117/): ImageSharp: CCITT fax decompression (T4/Modified Huffman): unbounded WriteBits overflows strip buffer — heap OOB write in SixLabors.ImageSharp (high 7.5)
- [CVE-2025-27598](https://insights.sbomify.com/CVE-2025-27598/): Out-of-bounds Write in SixLabors ImageSharp (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-106115 and fix it if it is affected.

What it is: CVE-2026-106115 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-106115 exists.

Affected packages and fixed versions:
- SixLabors.ImageSharp (NuGet): affected from 2.1.0; fixed in 3.2.0
- SixLabors.ImageSharp (NuGet): affected from 2.1.0; fixed in 3.2.0
- SixLabors.ImageSharp (NuGet): affected from 4.0.0; fixed in 4.1.2
- SixLabors.ImageSharp (NuGet): affected from 4.0.0; fixed in 4.1.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-106115/ (Markdown: https://insights.sbomify.com/CVE-2026-106115/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-106115
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-106115
- OSV: https://osv.dev/vulnerability/CVE-2026-106115

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-106115/
Summaries are generated and may contain mistakes; the official description above is the record.