CVE-2025-49113: Critical Vulnerability in Roundcube Webmail

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A severe vulnerability, CVE-2025-49113, has been identified in Roundcube, a widely-used open-source webmail client. With a CVSS score of 9.9, this flaw allows authenticated attackers to exploit PHP object injection via the `_from` parameter in upload.php, potentially leading to remote code execution (RCE).

Why It Matters

Exploiting this vulnerability could result in:

  • Remote execution of arbitrary code on the mail server.
  • Full compromise of hosted webmail environments.

Recommended Actions

  • Update Roundcube: Upgrade to version 1.6.11 or 1.5.10 to patch this vulnerability.
  • Restrict Access: Limit webmail access to trusted users and networks if patching is delayed.

Detection & Remediation Scripts

You Should Know:

1. Verify Roundcube Version

Run the following command to check your Roundcube version: 

grep -i "version" /var/www/roundcube/config/defaults.inc.php

2. Patch Immediately

If you’re running an affected version, update using:

 For Debian/Ubuntu 
sudo apt update && sudo apt install roundcube

For CentOS/RHEL 
sudo yum update roundcube

3. Check for Exploitation Attempts

Monitor logs for suspicious activity:

grep -r "_from=.php://" /var/log/roundcube/

4. Restrict File Uploads

Modify Roundcube’s configuration to restrict malicious uploads:

// Add to /var/www/roundcube/config/config.inc.php 
$config['file_upload_extensions'] = ['jpg', 'png', 'pdf'];

5. Disable Dangerous PHP Functions

Edit `php.ini` to disable risky functions:

disable_functions = "exec, shell_exec, system, passthru, popen"

6. Web Server Hardening

For Apache, restrict access:

<Directory "/var/www/roundcube">
Require ip 192.168.1.0/24 
</Directory>

For Nginx:

location /roundcube {
allow 192.168.1.0/24;
deny all;
}

7. Automate Detection with a Script

Save this as `check_cve.sh`:

!/bin/bash 
LOG_FILE="/var/log/roundcube/errors.log" 
if grep -q "CVE-2025-49113" "$LOG_FILE"; then 
echo "Exploit attempt detected!" 
exit 1 
fi

What Undercode Say

This vulnerability is extremely critical due to its high CVSS score and ease of exploitation. Attackers can take full control of email servers, leading to data breaches and lateral movement in networks.

Additional Linux & Windows Commands for Security

  • Check running PHP processes: 
    ps aux | grep php
  • Block suspicious IPs with iptables: 
    iptables -A INPUT -s 1.2.3.4 -j DROP
  • Windows: Check for malicious connections: 
    netstat -ano | findstr "ESTABLISHED"
  • Disable unnecessary services: 
    systemctl disable php-fpm

Expected Output:

  • Detection Script: Should return no exploit attempts.
  • Updated Roundcube: Version 1.6.11 or 1.5.10.
  • Restricted Access: Only trusted IPs can access /roundcube.

Prediction

This exploit will likely be massively abused in phishing campaigns, targeting businesses using Roundcube. Expect increased attacks in the next 30 days. Patch immediately or enforce strict access controls.

IT/Security Reporter URL:

Reported By: Roicohen Vrx – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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