# CVE-2026-64830: FFmpeg 2.1 - 8.1.2 Heap Buffer Overflow via VobSub Subtitle Demuxer

> Attackers can achieve arbitrary code execution by supplying a malicious VobSub subtitle file to applications using the FFmpeg library.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/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:** 22 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-64830, ECHO-f134-a339-73a5, GHSA-jphx-q7f7-4x8r, JLSEC-2026-1172, MINI-pj54-f4w7-v7f7, RHSA-2026:67276, RHSA-2026:67303, RHSA-2026:67309, UBUNTU-CVE-2026-64830

## What is CVE-2026-64830?

CVE-2026-64830 is a high-severity memory corruption vulnerability in Ffmpeg Ffmpeg, published on 22 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 versions 2.1 through 8.1.2 contains a heap buffer overflow vulnerability in the VobSub subtitle demuxer that allows attackers to corrupt adjacent heap memory by supplying a malicious .sub/.idx subtitle file declaring more distinct stream IDs than the fixed-size array bounds in libavformat/mpeg.c. Attackers can craft a subtitle file with excessive distinct stream IDs to trigger unbounded writes beyond the vobsub->q[] array boundary via ff_subtitles_queue_insert(), potentially achieving arbitrary code execution in any application using FFmpeg's VobSub demuxer.

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-64830?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ffmpeg` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-debugsource` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavcodec-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavcodec-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavcodec-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavdevice-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavdevice-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavdevice-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavfilter-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavfilter-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavfilter-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavformat-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavformat-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavformat-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavutil-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavutil-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavutil-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libpostproc-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libpostproc-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libpostproc-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libswresample-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libswresample-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libswresample-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libswscale-free-rhai` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libswscale-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `libswscale-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.3::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-debuginfo` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-debugsource` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-free-rhai` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `ffmpeg-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavcodec-free-rhai` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavcodec-free-rhai-debuginfo` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavcodec-free-rhai-devel` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |
| `libavdevice-free-rhai` | Red Hat:enterprise_linux_ai:3.4::el9 | All versions | 0:6.1.6-9.el9ai |

Products: Ffmpeg Ffmpeg.

## How do I fix CVE-2026-64830?

Apply the vendor's patch.

## Is CVE-2026-64830 being exploited?

There is no known exploitation of CVE-2026-64830 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-2026-64830 and fix it if it is affected.

What it is: CVE-2026-64830 is a high-severity memory corruption vulnerability in Ffmpeg Ffmpeg, published on 22 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-2026-64830 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-2026-64830/ (Markdown: https://insights.sbomify.com/CVE-2026-64830/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64830
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64830
- OSV: https://osv.dev/vulnerability/CVE-2026-64830

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64830/
Summaries are generated and may contain mistakes; the official description above is the record.