Vulnerability · Published Jul 24, 2026 · Assigned by VulnCheck

CVE-2026-66040FFmpeg Heap Out-of-Bounds Write via PNG/APNG eXIf Encoder

High 8.8

In plain English

A high-severity heap buffer overflow in FFmpeg from FFmpeg. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 56% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High

Exploit odds (30 days)0.8%top 44.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

FFmpeg through 8.1.2, fixed in commit b506faf, contains a heap out-of-bounds write vulnerability in the native PNG and APNG encoders that allows remote attackers to corrupt heap memory by supplying a crafted PNG image with a malicious eXIf chunk. Attackers can craft an eXIf chunk where multiple IFD entries reference the same large value payload, causing canonical serialization to expand the output far beyond the undersized allocation estimated by add_exif_profile_size(), resulting in png_write_chunk() writing tens of thousands of bytes past the buffer boundary, leading to deterministic heap corruption, process crash, and potentially arbitrary code execution.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	ffmpeg	no fix listed	DEBIAN-CVE-2026-66040
Debian:13	ffmpeg	no fix listed	DEBIAN-CVE-2026-66040
Debian:14	ffmpeg	7:9.0.2-1	DEBIAN-CVE-2026-66040
Ubuntu:26.10	ffmpeg	no fix listed	UBUNTU-CVE-2026-66040

Affected products (as reported)

Vendor	Product	Versions
FFmpeg	FFmpeg	0 – through 8.1.2

Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

Pull Request issue-tracking
Patch Commit patch
https://www.vulncheck.com/advisories/ffmpeg-heap-out-of-bounds-write-via-png-apng-exif-encoder third-party-advisory