5.4

CVE-2026-40930: pnggroup libpng Interpretation Conflict

CVSS: 5.4v3.1MediumAwaiting analysis
AliasesALPINE-CVE-2026-40930MGASA-2026-0205RHSA-2026:20356
Published 04-06-2026Last modified 04-06-2026
Open JSON

Vulnerability summary

CVE-2026-40930 is a medium (CVSS 5.4) Interpretation Conflict vulnerability in pnggroup libpng. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 27.7% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.4/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.36%
0%100%
Low · +0.15 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
USN-8639-1

Timeline

  1. 04-06-2026
    PublishedVulnerability first disclosed.
  2. 04-06-2026
    Last modifiedVulnerability information updated.

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 metrics

6 scores · 6 sources · 1 version

EPSS trend

Probability

0.36%

Chance of exploitation in the next 30 days

Percentile

28%

Versus all other CVEs

30-day change

+0.15 pp

From 0.20% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.36%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Redhat4 products
  • libpng< 0:1.6.58-1.hum1
  • libpng-devel< 0:1.6.58-1.hum1
  • libpng-static< 0:1.6.58-1.hum1
  • libpng-tools< 0:1.6.58-1.hum1
Pnggroup2 products
Alpine1 product
  • libpng< 1.6.59-r0 | < 1.6.58-r1
Debian1 product
  • libpng1.6< 1.6.37-4
Mageia1 product
  • libpng< 1.6.38-1.6.mga9
Ubuntu1 product
  • libpng1.6< 1.6.37-2ubuntu0.1~esm3 | < 1.6.37-3ubuntu0.6

6 vendors · 10 products

References

20 links
Show all 20 references