Path Traversal in Redaxo
CVE-2026-21857
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.
Vulnerability class: Path Traversal (Directory Traversal)
EPSS: 0.005 (39.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Redaxo — versions < 5.20.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-21857?
- CVE-2026-21857 is a medium-severity vulnerability in Redaxo, classified under Path Traversal. CVSS score: 6.5/10. Published 2026-01-07.
- How severe is CVE-2026-21857?
- Medium severity. CVSS v3 base score is 6.5 out of 10.
- Is CVE-2026-21857 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.