REDAXO CMS is vulnerable to Reflected XSS in Mediapool Info Banner via args[types]

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

• CVE-2025-66026: 0.29% estimated exploitation activity in the next 30 days; percentile 21.31 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A reflected Cross-Site Scripting (XSS) vulnerability exists in the Mediapool view where the request parameter args[types] is rendered into an info banner without HTML-escaping. This allows arbitrary JavaScript execution in the backend context when an authenticated user visits a crafted link while logged in. Details Control Flow: 1. redaxo/src/addons/mediapool/pages/index.php reads args via rexrequest('args', 'array') and passes them through as $argUrl to media.list.php. 2. redaxo/src/addons/mediapool/pages/media.list.php injects $argUrl['args']['types'] into an HTML string without escaping: PoC 1. Log into the REDAXO backend. 2. While authenticated, open a crafted URL like: <host/index.php?page=mediapool/media&args[types]="<img+src%3Dx+onerror%3Dalert%28document.domain%29 4. The info banner displays the unescaped value and activates the injected onerror handler, which opens an alert pop-up. Impact Arbitrary JavaScript execution in the backend, enabling theft of session…

Published by the source

25 Nov 2025, 23:53 UTC

Last modified by the source

27 Nov 2025, 09:01 UTC

Source last checked

26 Oct 2026, 14:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-x6vr-q3vf-vqgq

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# Patch Next advisory brief: CVE-2025-66026

Advisory: REDAXO CMS is vulnerable to Reflected XSS in Mediapool Info Banner via args[types]
IDs: CVE-2025-66026, GHSA-x6vr-q3vf-vqgq
Record: https://patchnext.com/advisories/cve-2025-66026 (revision 1, source checked 26 Oct 2026, 14:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: redaxo/source 5.20.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist redaxo/source: affected < 5.20.1; fixed in 5.20.1

## Suggested inspection (read-only)
- Packagist redaxo/source: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on redaxo/source.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-x6vr-q3vf-vqgq (GitHub-reviewed advisory GHSA-x6vr-q3vf-vqgq lists affected ranges: Packagist redaxo/source >=0 <5.20.1)

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