Medium severity · published Jun 4, 2026
CVE-2026-40930
LIBPNG: Chunk smuggling in push-mode APNG parser via unconsumed chunk body
5.4
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
Low
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 10% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
libpng · pnggroup
= 1.8.0 · source: vendor
LI
libpng-apng · pnggroup
>= 1.6.49, <= 1.6.57 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40930
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40930
github.com
https://github.com/pnggroup/libpng/commit/faf06924688b62d7c1654b5ceddedbde66ffadb4
github.com
https://github.com/pnggroup/libpng/security/advisories/GHSA-c4v6-gxrq-6g2x
www.openwall.com
http://www.openwall.com/lists/oss-security/2026/05/15/21
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4.4
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