---
id: CVE-2026-117538
title: REDAXO before 5.21.0 Reflected XSS via Packages API function Parameter
summary: >-
  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
  authentica…
severity: medium
cvss: 4.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:L'
cvssSource: cna
cwe:
  - CWE-79
vendor: redaxo
product: core
affected:
  - core < 5.21.0
published: '2026-10-27'
updated: '2026-10-27'
sourceUpdated: '2026-10-27T10:59:32.772Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-117538'
references:
  - url: 'https://github.com/redaxo/core/security/advisories/GHSA-xq4j-g85q-wf97'
    label: GitHub Security Advisory (GHSA-xq4j-g85q-wf97)
  - url: >-
      https://www.vulncheck.com/advisories/redaxo-before-5.21.0-reflected-xss-via-packages-api-function-parameter
    label: >-
      VulnCheck Advisory: REDAXO before 5.21.0 Reflected XSS via Packages API
      function Parameter
tags:
  - cve.org
ingestedAt: '2026-10-27T16:11:59.302Z'
---

## Overview

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

- `core < 5.21.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.