CVE-2026-21857 HIGH

CVE-2026-21857: Redaxo has Path Traversal in Backup Addon Leading to Arbitrary File Read

Vendor Redaxo
Product redaxo
Weakness CWE-24
Published January 7, 2026
Last update January 8, 2026
View on NVD All CVEs

CVSS base score

8.3/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N

What the vulnerability does

01Description

REDAXO is a PHP-based content management system. Prior to version 5.20.2, authenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality. The Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories. An attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive. Version 5.20.2 fixes this issue.

Key dates

02Disclosure timeline

January 7, 2026 CVE published
January 8, 2026 Record updated