CVE-2026-66039

8.7 HIGH 0.3% exploit odds Fix listed Memory safety

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-07-24 20:18 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-08-07 00:46 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 8.7 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-07-24 20:18 UTC
Last modified: 2026-08-07 00:46 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-122
Record status: Analyzed

Affected

Ffmpeg ≤ 8.1.2

Attack profile CVSS 4.0 · 8.7

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: Passive
Confidentiality: High
Integrity: High
Availability: High

Raw 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-66039.md and follow it. Check whether this project is affected by CVE-2026-66039. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record