Vulnerability · Published Oct 27, 2026 · Assigned by VulnCheck

CVE-2026-117538REDAXO before 5.21.0 Reflected XSS via Packages API function Parameter

Medium 4.1

In plain English

A medium-severity cross-site scripting in core from redaxo. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.1Medium

Exploit odds (30 days)0.2%top 92.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

REDAXO before 5.21.0 contains a reflected cross-site scripting vulnerability in the backend packages API, where the function parameter is concatenated into an error message rendered without HTML escaping. Attackers can lure an authenticated backend user to a crafted link containing a valid CSRF token, executing JavaScript that performs same-origin actions or reads DOM data.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	redaxo/source	5.21.0	GHSA-xq4j-g85q-wf97

Affected products (as reported)

Vendor	Product	Versions
redaxo	core	0 – before 5.21.0

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L

References

GitHub Security Advisory (GHSA-xq4j-g85q-wf97) vendor-advisory
VulnCheck Advisory: REDAXO before 5.21.0 Reflected XSS via Packages API function Parameter third-party-advisory