CVE-2026-66039: Ffmpeg

High severity, CVSS 7.8. EPSS: 0.4% chance of exploitation in the next 30 days.

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 products

• Ffmpeg Ffmpeg: up to and including 8.1.2

Published 2026-07-24. Last modified 2026-08-07.