# CVE-2026-75147: FFmpeg Out-of-Bounds Read in AV1 RTP Packetizer via rtpenc_av1.c

> A crafted AV1 packet triggers an out-of-bounds read in FFmpeg's RTP packetizer, potentially causing crashes or leaking memory contents.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 19 Aug 2026
- **Updated:** 27 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-75147, ECHO-2861-d781-30a1, GHSA-63qj-83cj-jp3m, UBUNTU-CVE-2026-75147

## What is CVE-2026-75147?

CVE-2026-75147 is a medium-severity memory corruption vulnerability in FFmpeg, published on 19 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

FFmpeg before commit 983dae9 contains an out-of-bounds read in the AV1 RTP packetizer (libavformat/rtpenc_av1.c). The keyframe detection loop that searches for a sequence header OBU advanced its pointer and remaining-size counter by the encoded header length plus the OBU payload size without first bounding the OBU size against the remaining data. A crafted OBU size causes the remaining-size counter to wrap to a positive value, causing the next loop iteration to dereference a pointer beyond the end of the packet buffer. A crafted AV1 input packet muxed to RTP triggers the out-of-bounds read.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-75147?


## How do I fix CVE-2026-75147?

Apply the vendor's patch.

## Is CVE-2026-75147 being exploited?

There is no known exploitation of CVE-2026-75147 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75147 and fix it if it is affected.

What it is: CVE-2026-75147 is a medium-severity memory corruption vulnerability in FFmpeg, published on 19 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-75147 in the wild and no public exploit code.

Affected product: 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-2026-75147/ (Markdown: https://insights.sbomify.com/CVE-2026-75147/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75147
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75147
- OSV: https://osv.dev/vulnerability/CVE-2026-75147

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75147/
Summaries are generated and may contain mistakes; the official description above is the record.