CVE-2026-66039: FFmpeg through 8.1.2, fixed in commit aafb5c6, contains a signed integer overflow vulnerability in the MACE6 a

Q: How do I fix CVE-2026-66039?

ffmpeg: upgrade to newer than 8.1.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-66039 being exploited?

CVE-2026-66039 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-66039 affect?

CVE-2026-66039 affects ffmpeg. Severity is high (CVSS 8.8). 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.

Routine

HIGH 8.8UPGRADE

CVE-2026-66039 is a high-severity flaw (CVSS 8.8) affecting ffmpeg. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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, resul

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 77%)
CISA exploited list	No
Weakness	CWE-122, CWE-190
Published	2026-07-24
Last modified	2026-08-07

Publisher (CNA): VulnCheck · Vendor: ffmpeg

Last updated 2026-08-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-24 20:18 UTCPublished CVE record published
2026-08-07 00:46 UTCUpdated Record last modified

ffmpeg ffmpeg UPGRADE

Affected: <= 8.1.2

Fixed in: newer than 8.1.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ffmpeg || rpm -q ffmpeg || ffmpeg --version

2. UPGRADE to newer than 8.1.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ffmpeg

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ffmpeg

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-66039?

ffmpeg: upgrade to newer than 8.1.2. Exact commands for each OS are on this page.

Is CVE-2026-66039 being exploited?

CVE-2026-66039 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-66039 affect?

CVE-2026-66039 affects ffmpeg. Severity is high (CVSS 8.8). 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.

How urgent is CVE-2026-66039?

Priority 37/100. High severity

Software pages

FFmpeg vulnerabilities

Related CVEs

CVE-2026-64831 HIGH 8.8 UPGRADE FFmpeg versions 8.0 through 8.1.2 contains a stack buffer overflow vulnerability in the Vulkan HEVC hardware d
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CVE-2026-64835 HIGH 8.8 UPGRADE FFmpeg versions 4.4 through 8.1.2 contain an out-of-bounds memory access vulnerability in the ADX audio decode
CVE-2026-64832 HIGH 8.8 UPGRADE FFmpeg versions 4.4 through 8.1.2 contain a double-free vulnerability in the NVIDIA NVDEC hardware decoder wit

References

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