CVE-2026-40930: Pnggroup Libpng

Medium severity, CVSS 5.4. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Pnggroup Libpng: version 1.8.0 only
• Pnggroup Libpng-Apng: from 1.6.49, up to and including 1.6.57

Published 2026-06-04. Last modified 2026-07-22.