CVE-2026-75143

Publication date 19 August 2026

Last updated 2 September 2026

Ubuntu priority

Cvss 3 Severity Score

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
ffmpeg	26.04 LTS resolute	Vulnerable
	24.04 LTS noble	Vulnerable
	22.04 LTS jammy	Vulnerable
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
libav	26.04 LTS resolute	Not in release
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release
	14.04 LTS trusty	Needs evaluation

Notes

leosilva

CVE-2026-75143: xenial/bionic/focal not-affected — libavformat/librist.c absent (introduced 4.4/jammy)

Severity score breakdown

CVSS version:

Base score 9.3 · Critical

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Attack requirements	None
Privileges required	None
User interaction	None
Vulnerable system - Confidentiality impact	High
Vulnerable system - Integrity impact	High
Vulnerable system - Availability impact	High
Subsequent system - Confidentiality impact	None
Subsequent system - Integrity impact	None
Subsequent system - Availability impact	None

Scores

Parameter	Value
Base score	9.3 · Critical
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Base score 9.8 · Critical