Vulnerability · Published Aug 19, 2026 · Assigned by VulnCheck

CVE-2026-75143FFmpeg Heap Buffer Overflow via RIST Protocol Reader

Critical 9.8

In plain English

A critical-severity heap buffer overflow 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 0.7% (higher than 53% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)0.7%top 46.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

FFmpeg before commit 1c10bcc contains a heap buffer overflow in the RIST protocol reader (libavformat/librist.c). librist_read() ignored its size argument and copied the full received payload length into the caller-provided destination buffer, overflowing it when the payload exceeds the destination size. This is reachable via the async:rist:// URL scheme, where the async wrapper supplies a smaller buffer than the received payload. A remote RIST sender can trigger the overflow by sending a packet whose payload exceeds the caller buffer size.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	ffmpeg	no fix listed	DEBIAN-CVE-2026-75143
Debian:13	ffmpeg	no fix listed	DEBIAN-CVE-2026-75143
Debian:14	ffmpeg	7:9.0.2-1	DEBIAN-CVE-2026-75143
Ubuntu:26.10	ffmpeg	no fix listed	UBUNTU-CVE-2026-75143

Affected products (as reported)

Vendor	Product	Versions
FFmpeg	FFmpeg	0 – before 1c10bcc2e17255dacb717a25ab3db142ce390602

Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Pull Request issue-tracking
Patch Commit patch
https://www.vulncheck.com/advisories/ffmpeg-heap-buffer-overflow-via-rist-protocol-reader third-party-advisory