CVE-2025-48200: TYPO3 sr_feuser_register RCE Vulnerability

CVE-2025-48200 Overview

CVE-2025-48200 is a critical Remote Code Execution (RCE) vulnerability affecting the sr_feuser_register extension through version 12.4.8 for TYPO3 content management system. This vulnerability stems from insecure deserialization (CWE-502), which allows attackers to execute arbitrary code on vulnerable TYPO3 installations without requiring authentication or user interaction.

Critical Impact

Attackers can achieve complete system compromise through unauthenticated remote code execution, potentially leading to full control over the TYPO3 web server and associated data.

Affected Products

• TYPO3 sr_feuser_register extension versions through 12.4.8
• TYPO3 CMS installations utilizing the vulnerable sr_feuser_register extension

Discovery Timeline

• 2025-05-21 - CVE-2025-48200 published to NVD
• 2025-05-21 - Last updated in NVD database

Technical Details for CVE-2025-48200

Vulnerability Analysis

This vulnerability allows remote attackers to execute arbitrary code on TYPO3 installations running the sr_feuser_register extension. The sr_feuser_register extension is a popular front-end user registration component for TYPO3 that handles user account creation and management workflows.

The vulnerability is classified under CWE-502 (Deserialization of Untrusted Data), indicating that the extension improperly processes serialized data from untrusted sources. When user-controlled input is deserialized without proper validation, attackers can craft malicious serialized payloads that, upon deserialization, trigger the instantiation of dangerous object types or the execution of arbitrary code.

The network-accessible attack vector with no authentication requirements makes this vulnerability particularly dangerous for internet-facing TYPO3 installations.

Root Cause

The root cause is insecure deserialization within the sr_feuser_register extension. The extension processes serialized PHP objects from user-controllable input without adequate validation or sanitization. When PHP's unserialize() function processes attacker-controlled data, it can instantiate objects with malicious properties that trigger code execution through magic methods such as __wakeup(), __destruct(), or other gadget chains available within the TYPO3 codebase.

Attack Vector

The attack is network-based and requires no privileges or user interaction. An attacker can remotely target the vulnerable extension endpoints by submitting crafted serialized payloads. The exploitation flow typically involves:

1. Identifying a TYPO3 installation with the vulnerable sr_feuser_register extension
2. Locating input vectors that accept serialized data
3. Crafting a malicious serialized payload leveraging available gadget chains
4. Submitting the payload to achieve arbitrary code execution on the target server

For technical exploitation details, refer to the TYPO3 Security Advisory.

Detection Methods for CVE-2025-48200

Indicators of Compromise

• Unusual HTTP requests to sr_feuser_register extension endpoints containing serialized PHP objects
• Presence of suspicious serialized data patterns (e.g., O: followed by class names) in web server access logs
• Unexpected process spawning or file system modifications originating from the web server process
• Anomalous outbound network connections from the TYPO3 server

Detection Strategies

• Monitor web application logs for requests containing serialized PHP object patterns targeting the sr_feuser_register extension
• Implement Web Application Firewall (WAF) rules to detect and block serialized object injection attempts
• Deploy endpoint detection and response (EDR) solutions to identify post-exploitation activities such as webshell deployment
• Utilize file integrity monitoring to detect unauthorized changes to TYPO3 installation files

Monitoring Recommendations

• Enable detailed logging for all HTTP requests to TYPO3 extensions
• Configure alerting for any detected deserialization attack patterns
• Monitor for new or modified PHP files within the TYPO3 installation directory
• Track process creation events on web servers for suspicious child processes

How to Mitigate CVE-2025-48200

Immediate Actions Required

• Upgrade the sr_feuser_register extension to a patched version immediately
• If patching is not immediately possible, consider temporarily disabling the sr_feuser_register extension
• Audit TYPO3 installations to identify all instances using the vulnerable extension
• Review server logs for signs of prior exploitation attempts

Patch Information

Refer to the official TYPO3 Security Advisory for specific patch details and updated extension versions. Update the sr_feuser_register extension through the TYPO3 Extension Manager or Composer to obtain the security fix.

Workarounds

• Disable the sr_feuser_register extension if user registration functionality is not critical
• Implement WAF rules to filter requests containing serialized PHP object patterns
• Restrict network access to TYPO3 administrative and extension endpoints using IP allowlisting
• Consider deploying a reverse proxy with input validation to sanitize incoming requests

# Example: Disable sr_feuser_register extension via TYPO3 CLI
./vendor/bin/typo3 extension:deactivate sr_feuser_register

# Verify extension status
./vendor/bin/typo3 extension:list | grep sr_feuser_register