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.
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)
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