Code execution via MACE6 sample-count overflow
Published Jul 24, 2026 · Updated Jul 24, 2026
Integer overflow in the MACE6 audio decoder in FFmpeg 8.1.2 and earlier allows attackers to execute code via a crafted CAF file. mace_decode_frame() computes the output sample count from attacker-controlled bytes_per_packet and frames_per_packet values without preventing signed overflow, causing an undersized allocation and heap out-of-bounds write. The victim must process attacker-controlled media with a build that includes the MACE6 decoder; successful exploitation corrupts heap memory in the decoding process.
Summary
What happened
Integer overflow in the MACE6 audio decoder in FFmpeg 8.1.2 and earlier allows attackers to execute code via a crafted CAF file. mace_decode_frame() computes the output sample count from attacker-controlled bytes_per_packet and frames_per_packet values without preventing signed overflow, causing an undersized allocation and heap out-of-bounds write. The victim must process attacker-controlled media with a build that includes the MACE6 decoder; successful exploitation corrupts heap memory in the decoding process.
The record
- CVE
- CVE-2026-66039
- Published
- Jul 24, 2026
- Updated
- Jul 24, 2026
- Vendor
- FFmpeg
- Product
- FFmpeg
- Classifications
- CWE-122, CWE-190, T1204.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 24, 2026CVE publishedPublication date reported by the CVE source.
- Jul 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=8.1.2
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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