Summary
REDAXO: Missing CSRF Protection on Package Update Action Allows Forced Addon Updates
The rex_api_install_package_update API function (install addon) does not override requiresCsrfProtection(), which defaults to false in the base class rex_api_function. Any authenticated admin can therefore be tricked via a CSRF attack into silently triggering a package update from the REDAXO package server.
Details
File: redaxo/src/core/lib/api_function.php:277-280
protected function requiresCsrfProtection()
{
return false; // DEFAULT, subclasses must opt in
}
File: redaxo/src/addons/install/lib/api/api_package_update.php:8-39
class rex_api_install_package_update extends rex_api_function
{
public function execute()
{
if (!rex::getUser()?->isAdmin()) {
throw new rex_api_exception('You do not have the permission!');
}
$addonkey = rex_request('addonkey', 'string');
$fileId = rex_request('file', 'int');
$installer = new rex_install_package_update();
// ... downloads and installs $addonkey version $fileId from redaxo.org
}
// requiresCsrfProtection() NOT overridden, defaults to false
}
For comparison, rex_api_install_package_add and rex_api_install_package_delete both correctly return true. Only rex_api_install_package_update is missing this.
PoC
<!-- Attacker-controlled page -->
<img src="https://victim-redaxo.example.com/index.php?page=install/packages&rex-api-call=install_package_update&addonkey=some_addon&file=42" />
When an authenticated admin visits this page, the request is automatically made with their session cookie, causing some_addon to be updated to version file_id=42.
Impact
An attacker who can lure an admin to a malicious page can force-install specific addon versions. If combined with a supply-chain compromise of a package on redaxo.org, or by targeting a downgrade to a known-vulnerable version, this becomes a remote code execution vector. Even without supply-chain compromise, it can be used to disrupt the site by forcing unwanted updates.
A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones. Typical impact: state-changing actions performed as the victim without their consent.
CVE-2026-63000 has a CVSS score of 6.4 (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 (5.21.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Add requiresCsrfProtection() to rex_api_install_package_update:
protected function requiresCsrfProtection()
{
return true;
}
Frequently Asked Questions
- What is CVE-2026-63000? CVE-2026-63000 is a medium-severity cross-site request forgery (CSRF) vulnerability in redaxo/source (composer), affecting versions <= 5.21.1. It is fixed in 5.21.2. A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones.
- How severe is CVE-2026-63000? CVE-2026-63000 has a CVSS score of 6.4 (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.
- Which versions of redaxo/source are affected by CVE-2026-63000? redaxo/source (composer) versions <= 5.21.1 is affected.
- Is there a fix for CVE-2026-63000? Yes. CVE-2026-63000 is fixed in 5.21.2. Upgrade to this version or later.
- Is CVE-2026-63000 exploitable, and should I be worried? Whether CVE-2026-63000 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
- What actually determines whether CVE-2026-63000 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.
- How do I fix CVE-2026-63000? Upgrade
redaxo/sourceto 5.21.2 or later.