Vulnerability · Published Aug 19, 2026 · Assigned by VulnCheck

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

Medium 5.8

In plain English

A medium-severity security flaw in FFmpeg from FFmpeg. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.8Medium

Exploit odds (30 days)0.2%top 95.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:14	ffmpeg	7:9.0.2-1	DEBIAN-CVE-2026-75145
Ubuntu:26.10	ffmpeg	no fix listed	UBUNTU-CVE-2026-75145

Affected products (as reported)

Vendor	Product	Versions
FFmpeg	FFmpeg	0 – before b4c199c5906ff53368926c2a5839881f41957e7f

Weakness: CWE-681 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:H

References

Pull Request issue-tracking
Patch Commit patch
https://www.vulncheck.com/advisories/ffmpeg-integer-narrowing-conversion-oob-memory-access-in-av1-rtp-packetizer third-party-advisory