CVE-2026-40930

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.

Score

CVSS 3.1 5.4 Medium

Status

Awaiting Analysis - security-advisories@github.com

Published

2026-06-04

Last modified

2026-06-04

Weaknesses

CWE-436

Affected products

• Libpng (Pnggroup)
• Libpng-apng (Pnggroup)

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