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.

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…

Vulnerability class: Buffer Overflow

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)

CWE-122 — Heap-based Buffer Overflow
CWE-190 — Integer Overflow or Wraparound

References

disclosure@vulncheck.com (patch)
disclosure@vulncheck.com (issue-tracking)
disclosure@vulncheck.com (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.