CVE-2026-66039 FFmpeg MACE6 Audio Decoder Heap Out-of-Bounds Write via CAF File
A signed integer overflow in FFmpeg's MACE6 decoder allows heap corruption and potential code execution via crafted CAF files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-66039?
CVE-2026-66039 is a high-severity vulnerability in Ffmpeg Ffmpeg, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Which versions are affected by CVE-2026-66039?
It affects 1 product.
Products include Ffmpeg Ffmpeg.
How do I fix CVE-2026-66039?
Apply the vendor's patch.
Is CVE-2026-66039 being exploited?
There is no known exploitation of CVE-2026-66039 in the wild and no public exploit code.
Other vulnerabilities in Ffmpeg Ffmpeg
Sources
Also known as DEBIAN-CVE-2026-66039, ECHO-96cc-ea04-811e, GHSA-84qc-6h9r-4w33, JLSEC-2026-1185, MINI-cg54-5cxx-pfxv, UBUNTU-CVE-2026-66039.