CVE-2026-40930

MEDIUM

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

Title source: cna

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.

References (3)

Core 3

Core References

X_Refsource_Confirm x_refsource_confirm

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

X_Refsource_Misc x_refsource_misc

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

View Writeup ZIP pw:eip

Mailing List

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

Scores

CVSS v3 5.4

EPSS 0.0020

EPSS Percentile 10.2%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact partial

Details

CWE

CWE-436

Status published

Products (2)

pnggroup/libpng = 1.8.0

pnggroup/libpng-apng >= 1.6.49, <= 1.6.57

Published Jun 04, 2026

Tracked Since Jun 04, 2026