# CVE-2026-66037: FFmpeg IAMF Demuxer Uncontrolled Resource Consumption via mix_presentation_obu()

> An attacker can cause denial of service in FFmpeg by triggering excessive memory allocation via a crafted IAMF file.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/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:** 28 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-66037, ECHO-db22-c42b-7dfb, GHSA-qqrg-chvw-q8jp, JLSEC-2026-1183, MINI-9ccp-9qjm-r2qw, UBUNTU-CVE-2026-66037

## What is CVE-2026-66037?

CVE-2026-66037 is a high-severity denial of service 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 through 8.1.2, fixed in commit 5d7112c, contains an uncontrolled resource consumption vulnerability in the IAMF demuxer that allows an unauthenticated attacker to cause multi-gigabyte memory allocation from a 17-byte input file by supplying a crafted count_label field. The mix_presentation_obu() function in libavformat/iamf_parse.c calls av_calloc(count_label, sizeof(*language_label)) with an attacker-controlled value before validating available OBU data, enabling an allocation amplification of approximately 126 million bytes per input byte that exhausts process memory or triggers an OOM-kill during format probing.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-66037?

It affects 1 product.


Products: Ffmpeg Ffmpeg.

## How do I fix CVE-2026-66037?

Apply the vendor's patch.

## Is CVE-2026-66037 being exploited?

There is no known exploitation of CVE-2026-66037 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-2026-66037 and fix it if it is affected.

What it is: CVE-2026-66037 is a high-severity denial of service 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-2026-66037 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-2026-66037/ (Markdown: https://insights.sbomify.com/CVE-2026-66037/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66037
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66037
- OSV: https://osv.dev/vulnerability/CVE-2026-66037

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-66037/
Summaries are generated and may contain mistakes; the official description above is the record.