# CVE-2026-106116: ImageSharp: BigTIFF IFD count can keep a decoder thread in a non-progressing loop

> Attackers can cause a denial of service by forcing a decoder thread into an infinite loop using a malformed BigTIFF image.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **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:** 6 Oct 2026
- **Also known as:** ECHO-c871-d275-7ef9, GHSA-wmxv-xphr-5c9g

## What is CVE-2026-106116?

CVE-2026-106116 is a medium-severity denial of service 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 2.0.0 until 4.1.2, ExifReader.ReadValues64 trusts the 64-bit BigTIFF IFD entry count and iterates once per declared entry. When fewer than 20 bytes remain, ExifReader.ReadValue64 returns without advancing the stream or terminating the outer loop, so a small malformed BigTIFF can keep one decoder thread executing for an attacker-controlled duration. This report does not claim worker-pool exhaustion. This issue is fixed in version 4.1.2.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2026-106116?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `SixLabors.ImageSharp` | NuGet | From 2.0.0 | 3.2.0 |
| `SixLabors.ImageSharp` | NuGet | From 2.0.0 | 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-2026-106116?

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

## Is CVE-2026-106116 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-106116 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-2026-106115](https://insights.sbomify.com/CVE-2026-106115/): ImageSharp: TIFF CCITT T6 encoder writes beyond an undersized output buffer (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)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-106116 and fix it if it is affected.

What it is: CVE-2026-106116 is a medium-severity denial of service 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-2026-106116 exists.

Affected packages and fixed versions:
- SixLabors.ImageSharp (NuGet): affected from 2.0.0; fixed in 3.2.0
- SixLabors.ImageSharp (NuGet): affected from 2.0.0; 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-2026-106116/ (Markdown: https://insights.sbomify.com/CVE-2026-106116/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-106116
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-106116
- OSV: https://osv.dev/vulnerability/CVE-2026-106116

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-106116/
Summaries are generated and may contain mistakes; the official description above is the record.