CVE-2026-66039

FFmpeg MACE6 Audio Decoder Heap Out-of-Bounds Write via CAF File

Published Jul 24, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8671-1 FFmpeg vulnerabilities
Ubuntu USN Ubuntu USN USN-8738-1 FFmpeg vulnerabilities
History
Type Values Removed Values Added
CPEs cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Ffmpeg
Ffmpeg ffmpeg
Vendors & Products Ffmpeg
Ffmpeg ffmpeg
Type Values Removed Values Added
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.
Title FFmpeg MACE6 Audio Decoder Heap Out-of-Bounds Write via CAF File
Weaknesses CWE-122
CWE-190
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Jul 29, 2026, 3:55 AM
Reserved
Jul 23, 2026, 8:45 PM
Status
Analyzed
Published
Jul 24, 2026, 8:18 PM
Modified
Aug 7, 2026, 12:46 AM
Severity
Important
Public date
Jul 24, 2026, 7:42 PM