CVE-2026-65704

Publication date 23 July 2026

Last updated 28 August 2026

Ubuntu priority

Cvss 3 Severity Score

Description

FFmpeg through 8.1.2 contains an out-of-bounds write vulnerability that allows attackers to cause heap corruption by supplying a crafted ffconcat file processed with the -safe 0 flag. The TY demuxer's demux_audio() function decrements packet size without bounds checking, producing a negative size value that is passed to memcpy() in shorten_decode_frame(), where conversion to size_t wraps the value to near SIZE_MAX and triggers reads beyond the source allocation and writes far beyond the Shorten decoder's bitstream buffer.

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	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-2026-65704: xenial/bionic not-affected — libavformat/ty.c demuxer absent, vulnerable demux_audio() underflow path unreachable.

Severity score breakdown

CVSS version:

Base score 7.3 · High

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	Low
Attack requirements	Present
Privileges required	None
User interaction	Passive
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	7.3 · High
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

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

Base score 7.8 · High