Admidio is an open-source user management solution. Prior to version 4.3.12, an unsafe deserialization vulnerability allows any unauthenticated user to execute arbitrary code on the server. Version 4.3.12 fixes this issue.

Affected: Packagist: admidio/admidio

### Summary An unsafe deserialization vulnerability allows any unauthenticated user to execute arbitrary code on the server.

### PoC 1. Go to https://www.admidio.org/demo_en/adm_program/modules/messages/messages.php 2. Click on Send Private Message 3. In the `Message` field, enter the following payload `Testing<br><h1>HTML</h1><br><h2>Injection</h2>`

> 

4. Send the message 5. Open the message again

> 

### Impact 1. Data Theft: Stealing sensitive information like cookies, session tokens, and user credentials. 2. Session Hijacking: Gaining unauthorized access to user accounts. 3. Phishing: Tricking users into revealing sensitive information. 4. Website Defacement: Altering the appearance or content of the website. 5. Malware Distribution: Spreading malware to users' devices. 6. Denial of Service (DoS): Overloading the server with malicious requests.