CVE-2026-40930

EUVD-2026-34287
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.4 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Debian logo
Debian Releases
Debian Product
Codename
libpng1.6
bookworm
1.6.39-2+deb12u5
fixed
bookworm (security)
1.6.39-2+deb12u5
fixed
bullseye
postponed
bullseye (security)
vulnerable
forky
1.6.58-1
fixed
sid
1.6.58-1
fixed
trixie
1.6.48-1+deb13u5
fixed
trixie (security)
1.6.48-1+deb13u5
fixed
Common Weakness Enumeration
References
https://github.com/pnggroup/libpng/commit/faf06924688b62d7c1654b5ceddedbde66ffadb4
https://github.com/pnggroup/libpng/security/advisories/GHSA-c4v6-gxrq-6g2x
http://www.openwall.com/lists/oss-security/2026/05/15/21