# CVE-2026-66041: FFmpeg 7.0 - 8.1.2 Heap Out-of-Bounds Write via vf_quirc Filter

> Heap out-of-bounds write in FFmpeg's vf_quirc filter allows attackers to execute code or crash the application via crafted subtitle files.

- **Severity:** High 7.7 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 24 Jul 2026
- **Updated:** 29 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-66041, GHSA-frhp-m687-9g3q, JLSEC-2026-1187, MINI-rp5p-f8pw-rv8x, UBUNTU-CVE-2026-66041

## What is CVE-2026-66041?

CVE-2026-66041 is a high-severity memory corruption vulnerability in Ffmpeg Ffmpeg, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

FFmpeg 7.0 through 8.1.2, fixed in commit 4da9812, contains a heap out-of-bounds write vulnerability in the vf_quirc filter that allows an attacker to corrupt heap memory by supplying a crafted PGS/SUP subtitle file with mismatched frame dimensions. Attackers can provide a subtitle file whose second presentation has larger dimensions than its first, causing av_image_copy_plane() to copy data exceeding the initial allocation size into the undersized libquirc grayscale image buffer, resulting in heap corruption and process crash with potential for code execution.

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

## Which versions are affected by CVE-2026-66041?

It affects 1 product.


Products: Ffmpeg Ffmpeg.

## How do I fix CVE-2026-66041?

Apply the vendor's patch.

## Is CVE-2026-66041 being exploited?

There is no known exploitation of CVE-2026-66041 in the wild and no public exploit code.

## Other vulnerabilities in Ffmpeg Ffmpeg

- [CVE-2013-0864](https://insights.sbomify.com/CVE-2013-0864/): Memory corruption in n/a (critical 10.0)
- [CVE-2013-0872](https://insights.sbomify.com/CVE-2013-0872/): Memory corruption in n/a (critical 10.0)
- [CVE-2013-0873](https://insights.sbomify.com/CVE-2013-0873/): Memory corruption in n/a (critical 10.0)
- [CVE-2013-4265](https://insights.sbomify.com/CVE-2013-4265/): Null dereference in n/a (critical 10.0)
- [CVE-2011-3937](https://insights.sbomify.com/CVE-2011-3937/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66041 and fix it if it is affected.

What it is: CVE-2026-66041 is a high-severity memory corruption vulnerability in Ffmpeg Ffmpeg, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-66041 in the wild and no public exploit code.

Affected product: Ffmpeg Ffmpeg. 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-2026-66041/ (Markdown: https://insights.sbomify.com/CVE-2026-66041/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66041
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66041
- OSV: https://osv.dev/vulnerability/CVE-2026-66041

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-66041/
Summaries are generated and may contain mistakes; the official description above is the record.