CVE-2026-75146

Publication date 19 August 2026

Last updated 2 September 2026

Ubuntu priority

Cvss 3 Severity Score

Description

FFmpeg before commit 65b0dab contains an out-of-bounds read in the DASH demuxer (libavformat/dashdec.c). When a live DASH manifest is refreshed with a startNumber that is lower than the previous value, the current sequence number is driven negative. The fragment retrieval function checked only the upper bound before indexing the fragments array, allowing a negative index to be used and causing an out-of-bounds read. A malicious or misconfigured DASH server can trigger this by serving a live manifest with a decreasing startNumber across a manifest refresh.

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	Vulnerable
	18.04 LTS bionic	Vulnerable
	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-2026-75146: xenial not-affected — libavformat/dashdec.c absent (introduced 3.4/bionic)

Severity score breakdown

CVSS version:

Base score 7.2 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Attack requirements	None
Privileges required	None
User interaction	Passive
Vulnerable system - Confidentiality impact	High
Vulnerable system - Integrity impact	None
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	7.2 · High
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

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

Base score 8.1 · High