CVE-2026-65704

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-23 20:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-07 00:16 UTC Last updatedMost recent change to the record

Details

Published

2026-07-23 20:17 UTC

Last modified

2026-08-07 00:16 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-191

Record status

Analyzed

Affected

• Ffmpeg ≤ 8.1.2

Attack profile CVSS 4.0 · 7.3

Attack vector

Local

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

Passive

Confidentiality

High

Integrity

High

Availability

High