# CVE-2026-5186: Nothings stb Multi-frame GIF File stb_image.h stbi__load_gif_main double free

> A double free vulnerability in the stb image library's GIF handler allows local attackers to potentially execute code or cause denial of service.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Mar 2026
- **Updated:** 31 Mar 2026
- **Also known as:** BELL-CVE-2026-5186, DEBIAN-CVE-2026-5186, GHSA-593x-hf83-hmrv, UBUNTU-CVE-2026-5186

## What is CVE-2026-5186?

CVE-2026-5186 is a medium-severity use after free vulnerability in Nothings stb, published on 31 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A weakness has been identified in Nothings stb up to 2.30. This impacts the function stbi__load_gif_main of the file stb_image.h of the component Multi-frame GIF File Handler. This manipulation causes double free. The attack requires local access. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-415 (Double Free), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-5186?


## How do I fix CVE-2026-5186?

No fix has been published for CVE-2026-5186 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-5186 being exploited?

There is no known exploitation of CVE-2026-5186 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5186 and fix it if it is affected.

What it is: CVE-2026-5186 is a medium-severity use after free vulnerability in Nothings stb, published on 31 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-5186 in the wild and no public exploit code.

Affected product: Nothings stb. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-5186/ (Markdown: https://insights.sbomify.com/CVE-2026-5186/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5186
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5186
- OSV: https://osv.dev/vulnerability/CVE-2026-5186

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5186/
Summaries are generated and may contain mistakes; the official description above is the record.