Vulnerability · Published Jul 24, 2026 · Assigned by VulnCheck

CVE-2026-66039FFmpeg MACE6 Audio Decoder Heap Out-of-Bounds Write via CAF File

High 8.8

In plain English

A high-severity integer 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 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High

Exploit odds (30 days)0.3%top 76.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

FFmpeg through 8.1.2, fixed in commit aafb5c6, contains a signed integer overflow vulnerability in the MACE6 audio decoder that allows attackers to corrupt heap memory by supplying a crafted CAF file with a malicious bytes_per_packet value. Attackers can craft a CAF file with oversized bytes_per_packet and frames_per_packet values in the desc chunk to trigger an integer overflow in mace_decode_frame() during output sample count computation, resulting in an undersized buffer allocation and heap out-of-bounds write that could enable code execution.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	ffmpeg	no fix listed	DEBIAN-CVE-2026-66039
Debian:13	ffmpeg	no fix listed	DEBIAN-CVE-2026-66039
Debian:14	ffmpeg	7:9.0.2-1	DEBIAN-CVE-2026-66039
Ubuntu:26.10	ffmpeg	no fix listed	UBUNTU-CVE-2026-66039

Affected products (as reported)

Vendor	Product	Versions
FFmpeg	FFmpeg	0 – through 8.1.2

Weakness: CWE-190, CWE-122 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

Pull Request issue-tracking
Patch Commit patch
https://www.vulncheck.com/advisories/ffmpeg-mace6-audio-decoder-heap-out-of-bounds-write-via-caf-file third-party-advisory