high CVSS 8.8

CVE-2026-32756·PHP vulnerability

Admidio is an open-source user management solution. Versions 5.0.6 and below contain a critical unrestricted file upload vulnerability in the Documents & Files module. Due to a design flaw in how CSRF token validation and file extension verification interact within UploadHandlerFile.php, an authenticated user with upload permissions can bypass file extension restrictions by intentionally submitting an invalid CSRF token. This allows the upload of arbitrary file types, including PHP scripts, which may lead to Remote Code Execution on the server, resulting in full server compromise, data exfiltration, and lateral movement. This issue has been fixed in version 5.0.7.

Severity
high
Software
PHP
Fixed in
5.0.7
Published
2026-03-20

Affected versions

Until: 5.0.7

Fixed in: 5.0.7

How to fix this CVE

Update Admidio to version 5.0.7 or later to patch the unrestricted file upload vulnerability in the Documents & Files module. The vulnerability allows authenticated users to circumvent file extension restrictions and upload malicious PHP files by exploiting a flaw in CSRF token validation logic. Immediately upgrade your installation and review uploaded files for any suspicious PHP scripts that may have been uploaded during the exposure window.

sudo dnf update php

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

POST /adm/modules/documents/upload_file.php.*csrf.*([A-Za-z0-9]+\.(php|phtml|php3|php4|php5|phar|phps|shtml))

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

Implement WAF rules to block POST requests to Admidio upload endpoints that contain missing or malformed CSRF tokens in the request body or headers. Additionally, enforce strict Content-Type validation and block multipart uploads with executable MIME types (application/x-php, application/x-httpd-php, text/x-php) regardless of file extension.

How to check if you are affected

  1. Step 1: Check the installed Admidio version by examining the VERSION file or querying the database: `grep -r 'VERSION\|version' /path/to/admidio/` or check the web interface admin panel.
  2. Step 2: Verify if the Documents & Files module is enabled and accessible to authenticated users by testing file upload functionality with a test account.
  3. Step 3: Search web server logs for POST requests to upload endpoints with invalid CSRF tokens: `grep -i 'upload\|csrf' /var/log/apache2/access.log | grep -v '2[0-9][0-9]'`
  4. Step 4: Confirm the patch by checking if Admidio version is 5.0.7 or higher: `grep -i 'VERSION' /path/to/admidio/VERSION` should show 5.0.7+

FAQ

What is CVE-2026-32756?

CVE-2026-32756 is a critical file upload vulnerability in Admidio's Documents & Files module that allows authenticated users to bypass file type restrictions by submitting invalid CSRF tokens, enabling the upload and execution of arbitrary PHP files on the server.

Is CVE-2026-32756 being actively exploited?

No, this vulnerability is not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available, though the high severity and ease of exploitation warrant immediate patching.

What versions of Admidio are affected by CVE-2026-32756?

All versions of Admidio up to and including 5.0.6 are vulnerable; version 5.0.7 and later contain the fix.

How do I check if my server is vulnerable to CVE-2026-32756?

Check your Admidio version by viewing the VERSION file or admin panel settings. If it shows 5.0.6 or below and the Documents & Files module is enabled for authenticated users, your system is vulnerable.

Does Defensia detect CVE-2026-32756?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Admidio is installed on a monitored server, CVE-2026-32756 will appear in your dashboard with remediation steps.

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References

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