Arbitrary file upload in Piwigo

CVE-2026-42322

Piwigo is a full featured open source photo gallery application for the web. Prior to 16.4.0, admin/themes_standard_pages.php validates uploaded logo content by MIME type but reuses the attacker-controlled extension from std_pgs_logo when constructing the stored filename. An authenticated administrator can upload image content with a server-executable final extension, causing the file to be placed in the web-accessible logo directory and executed when requested if the web server handles that extension. This can permit arbitrary command execution, data disclosure, modification, persistence, and service disruption. This vulnerability is fixed in 16.4.0.

Vulnerability class: Unrestricted File Upload

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.013 (70.2th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 70.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-42322: rose from 0.005 to 0.013.

EPSS over last 30 days · oldest: 0.005 · newest: 0.013 · change: +0.007

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-42322?
CVE-2026-42322 is a critical-severity vulnerability in Piwigo, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.1/10. Published 2026-09-25.
How severe is CVE-2026-42322?
Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2026-42322 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.