Buffer overflow in Ffmpeg
CVE-2026-66039
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.
Vulnerability class: Buffer Overflow
EPSS: 0.003 (23.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Ffmpeg — versions 0, aafb5c655edc76a753275c383ebb139feb032718
Weakness classification (CWE)
References
- disclosure@vulncheck.com (Patch, patch)
- disclosure@vulncheck.com (issue-tracking, Patch, Issue Tracking)
- disclosure@vulncheck.com (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-66039?
- CVE-2026-66039 is a high-severity vulnerability in Ffmpeg, classified under Heap-based Buffer Overflow. CVSS score: 8.8/10. Published 2026-07-24.
- How severe is CVE-2026-66039?
- High severity. CVSS v3 base score is 8.8 out of 10.