CVE-2025-66026 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in redaxo/source. A fix is available for redaxo/source — see the affected versions and patch details below.
REDAXO is Vulnerable to Reflected XSS in Mediapool Info Banner via args[types]
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-66026.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
redaxo/sourceReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
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:
redaxo/src/addons/mediapool/pages/index.phpreads args viarex_request('args', 'array')and passes them through as$argUrltomedia.list.php.redaxo/src/addons/mediapool/pages/media.list.phpinjects$argUrl['args']['types']into an HTML string without escaping:
if (!empty($argUrl['args']['types'])) {
echo rex_view::info(rex_i18n::msg('pool_file_filter') . ' <code>' . $argUrl['args']['types'] . '</code>');
}
PoC
- Log into the REDAXO backend.
- While authenticated, open a crafted URL like:
<host>/index.php?page=mediapool/media&args[types]="><img+src%3Dx+onerror%3Dalert%28document.domain%29> - 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 cookies, CSRF tokens, or other sensitive data, and allowing an attacker to perform any administrative actions on behalf of the affected user.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | redaxo/source | all versions | 5.20.1composer require redaxo/source:^5.20.1 |
Affected Products
redaxoredaxoDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for redaxo/source, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update redaxo/source to 5.20.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-66026 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2025-66026 in your dependencies?
Find it across Packagist, including transitive dependencies.