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.
CVE-2026-21857
This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 91% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(medium)
- EG Risk
- —
- EPSS
- 39.4%
- KEV
- Not listed
Published
January 7, 2026
Last Modified
January 20, 2026
References (3)
- security-advisories@githubhttps://github.com/redaxo/redaxo/releases/tag/5.20.2
- security-advisories@githubhttps://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
- 134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv
Affected Packages
(1 across 1 ecosystem)
Packagist(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| redaxo/source | 5.10.0 ... 5.20.1 (40 versions) | 5.20.2 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 43× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
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Related CVEs(same CWE)
Same CWE
10 shownCWE-22
Frequently asked(5)
What is CVE-2026-21857?
When was CVE-2026-21857 disclosed?
Is CVE-2026-21857 actively exploited?
What is the CVSS score of CVE-2026-21857?
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Dependency Blast Radius
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