| Name | CVE-2026-40930 |
| Description | LIBPNG is a reference library for use in applications that process PNG (Portable Network Graphics) raster image files. In version 1.8.0, three inter-frame chunk discard paths in the push-mode APNG parser clear the chunk-header flag without consuming the chunk body and CRC, allowing attacker-controlled bytes inside an ignored ancillary chunk to be reinterpreted as a fresh chunk header on the next call to `png_process_data`. Commit faf06924688b62d7c1654b5ceddedbde66ffadb4 fixes the issue. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| libpng1.6 (PTS) | bullseye | 1.6.37-3 | vulnerable |
| bullseye (security) | 1.6.37-3+deb11u4 | vulnerable |
| bookworm, bookworm (security) | 1.6.39-2+deb12u5 | fixed |
| trixie (security), trixie | 1.6.48-1+deb13u5 | fixed |
| forky, sid | 1.6.58-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| libpng1.6 | source | (unstable) | 1.6.37-4 | | | |
Notes
[bullseye] - libpng1.6 <postponed> (Minor issue, not exploitable in default configuration, unclear impact)
The vulnerable code has its roots in the external libpng-apng patchset for 1.6
1.8 development releases adopted the patch which then introduced it into libpng
The apng patch was applied in Deian starting with 1.6.36-2 and dropped in 1.6.37-4,
so marking 1.6.37-4 as the fixed version
https://github.com/pnggroup/libpng/security/advisories/GHSA-c4v6-gxrq-6g2x
https://github.com/pnggroup/libpng/commit/faf06924688b62d7c1654b5ceddedbde66ffadb4