CVE-2025-66026

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 rex_request('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:

if (!empty($argUrl['args']['types'])) {
    echo rex_view::info(rex_i18n::msg('pool_file_filter') . ' <code>' . $argUrl['args']['types'] . '</code>');
}

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>
3. The info banner displays the unescaped value and activates the injected onerror handler, which opens an alert pop-up.

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.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2025-66026 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.20.1); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-66026? CVE-2025-66026 is a medium-severity cross-site scripting (XSS) vulnerability in redaxo/source (composer), affecting versions < 5.20.1. It is fixed in 5.20.1. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2025-66026? CVE-2025-66026 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of redaxo/source are affected by CVE-2025-66026? redaxo/source (composer) versions < 5.20.1 is affected.
4. Is there a fix for CVE-2025-66026? Yes. CVE-2025-66026 is fixed in 5.20.1. Upgrade to this version or later.
5. Is CVE-2025-66026 exploitable, and should I be worried? Whether CVE-2025-66026 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-66026 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-66026? Upgrade redaxo/source to 5.20.1 or later.