CVE-2026-40930

MEDIUM5.4

LIBPNG: Chunk smuggling in push-mode APNG parser via unconsumed chunk body

Published Jun 4, 2026

Modified 3 weeks ago

Details

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.

References

WEB

http://www.openwall.com/lists/oss-security/2026/05/15/21

WEB

https://github.com/pnggroup/libpng/commit/faf06924688b62d7c1654b5ceddedbde66ffadb4

WEB

https://github.com/pnggroup/libpng/security/advisories/GHSA-c4v6-gxrq-6g2x

ADVISORY

https://www.cve.org/CVERecord?id=CVE-2026-40930

CVSS Analysis

CVSS v3.1

5.4