# CVE-2026-75145: FFmpeg Integer Narrowing Conversion OOB Memory Access in AV1 RTP Packetizer

> An integer narrowing error in FFmpeg's AV1 RTP packetizer allows out-of-bounds memory access, potentially leading to code execution or crashes.

- **Severity:** Medium 5.8 (`CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:P/VC:L/VI:L/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-2026-75145, ECHO-37b9-2184-9e46, GHSA-6fh5-pxvv-ccvw, UBUNTU-CVE-2026-75145

## What is CVE-2026-75145?

CVE-2026-75145 is a medium-severity 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 b4c199c contains an incorrect integer narrowing conversion in the AV1 RTP packetizer (libavformat/rtpenc_av1.c). The OBU size is cast to long before comparison against the remaining frame size. On targets where long is 32 bits, including 64-bit Windows, sufficiently large OBU size values are sign-flipped by the narrowing cast, producing a negative value that passes the payload size check. This allows an oversized OBU to bypass the safety bound on affected platforms, leading to out-of-bounds memory access when the oversized value is subsequently used as a copy length.

Weakness: CWE-681 (Incorrect Conversion between Numeric Types)

## Which versions are affected by CVE-2026-75145?


## How do I fix CVE-2026-75145?

Apply the vendor's patch.

## Is CVE-2026-75145 being exploited?

There is no known exploitation of CVE-2026-75145 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75145 and fix it if it is affected.

What it is: CVE-2026-75145 is a medium-severity 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-2026-75145 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-2026-75145/ (Markdown: https://insights.sbomify.com/CVE-2026-75145/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75145
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75145
- OSV: https://osv.dev/vulnerability/CVE-2026-75145

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75145/
Summaries are generated and may contain mistakes; the official description above is the record.