What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-24 · updated 2026-08-07
• Weakness: CWE-122

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 products

• FFmpeg: through 8.1.2

References

• https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/aafb5c655edc76a753275c383ebb139feb032718
• https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23631
• https://www.vulncheck.com/advisories/ffmpeg-mace6-audio-decoder-heap-out-of-bounds-write-via-caf-file

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