Summary
Several administrative operations in Admidio's preferences module (database backup, test email, htaccess generation) fire via GET requests with no CSRF token validation. Because SameSite=Lax cookies travel with top-level GET navigations, an attacker forces an authenticated admin to trigger these actions from a malicious page.
Details
In modules/preferences.php, the backup, test_email, and htaccess modes accept GET parameters with no CSRF token check:
// modules/preferences.php - backup mode
case 'backup':
// Creates full database dump and serves as download
// No CSRF token validation
$backupFile = $gDb->backup();
// ... sends file to client
break;
case 'test_email':
// Sends test email from the server
// No CSRF token validation
break;
case 'htaccess':
// Writes .htaccess file to disk
// No CSRF token validation
break;
The save mode in the same file validates CSRF via getFormObject(), confirming the developers intended CSRF protection but did not apply it to these other modes.
Because these are GET requests, SameSite=Lax browsers include session cookies on top-level cross-origin navigations, making CSRF exploitation trivial.
Proof of Concept
Simplified attacker page (csrf.html hosted on attacker origin):
<html>
<body>
<h1>Loading...</h1>
<!-- Trigger backup creation on victim's browser -->
<script>window.location = 'https://target-admidio.example.com/adm_program/modules/preferences.php?mode=backup';</script>
</body>
</html>
When an administrator visits this page, the browser navigates to the Admidio backup URL with full session cookies. The server generates a database dump and serves it as a download to the victim's browser. Note: the backup downloads to the victim's machine, not to the attacker. The attacker cannot read the response cross-origin.
For htaccess mode, the CSRF overwrites the .htaccess file on the server, disrupting the application. For test_email mode, it triggers email sends from the server, which an attacker can abuse for spam or to probe internal email infrastructure.
Impact
An attacker tricks an Admidio administrator into visiting a malicious page that triggers state-changing operations on the server:
- Backup creation: forces the server to generate a full database dump. The backup downloads to the victim's browser, not to the attacker. However, repeated backup triggers can cause disk I/O and storage pressure on the server.
- htaccess modification: overwrites the server's
.htaccessfile, breaking URL routing or disabling security headers. - Test email: fires email sends from the server, usable as a spam relay or to probe internal mail configuration.
The core issue is that state-changing operations run via unprotected GET requests. The victim only needs to visit a single attacker-controlled page while logged in.
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-2026-41663 has a CVSS score of 3.5 (Low). The vector is network-reachable, high 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 (5.0.9); 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.
Remediation advice
- Change
backup,test_email, andhtaccessoperations to require POST requests. - Add CSRF token validation using the existing
getFormObject()mechanism. - As defense in depth, set
SameSite=Stricton session cookies or add a confirmation step for destructive operations like database backup.
Found by aisafe.io
Frequently Asked Questions
- What is CVE-2026-41663? CVE-2026-41663 is a low-severity cross-site request forgery (CSRF) vulnerability in admidio/admidio (composer), affecting versions <= 5.0.8. It is fixed in 5.0.9. 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-2026-41663? CVE-2026-41663 has a CVSS score of 3.5 (Low). 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 admidio/admidio are affected by CVE-2026-41663? admidio/admidio (composer) versions <= 5.0.8 is affected.
- Is there a fix for CVE-2026-41663? Yes. CVE-2026-41663 is fixed in 5.0.9. Upgrade to this version or later.
- Is CVE-2026-41663 exploitable, and should I be worried? Whether CVE-2026-41663 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-2026-41663 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-2026-41663? Upgrade
admidio/admidioto 5.0.9 or later.