CVE-2025-5514
📋 TL;DR
A remote unauthenticated attacker can send specially crafted HTTP requests to exploit an improper length parameter handling vulnerability in Mitsubishi Electric MELSEC iQ-F Series CPU modules. This causes the web server function to delay processing, creating a denial-of-service condition that prevents legitimate users from accessing the web interface. Industrial control systems using these vulnerable PLC modules are affected.
💻 Affected Systems
- Mitsubishi Electric MELSEC iQ-F Series CPU modules
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of web server functionality, preventing operators from monitoring or controlling industrial processes via the web interface, potentially disrupting operations.
Likely Case
Temporary web server unavailability requiring restart of the CPU module to restore functionality.
If Mitigated
Minimal impact with proper network segmentation and monitoring detecting anomalous HTTP traffic patterns.
🎯 Exploit Status
Exploitation requires sending specially crafted HTTP requests but does not require authentication. The vulnerability is in the web server's request handling logic.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Mitsubishi Electric security advisory for specific firmware versions
Vendor Advisory: https://www.mitsubishielectric.com/psirt/vulnerability/pdf/2025-010_en.pdf
Restart Required: Yes
Instructions:
1. Download the security patch from Mitsubishi Electric's support portal. 2. Backup current configuration and program. 3. Apply firmware update following manufacturer instructions. 4. Restart the CPU module. 5. Verify web server functionality.
🔧 Temporary Workarounds
Network Segmentation
allIsolate MELSEC iQ-F Series PLCs in dedicated industrial network segments with strict firewall rules limiting access to authorized systems only.
Disable Web Server
allIf web server functionality is not required, disable it in the PLC configuration to eliminate the attack surface.
🧯 If You Can't Patch
- Implement strict network access controls allowing only trusted IP addresses to communicate with the PLC web interface
- Deploy network monitoring and intrusion detection systems to detect anomalous HTTP traffic patterns targeting the PLC
🔍 How to Verify
Check if Vulnerable:
Check firmware version against Mitsubishi Electric's security advisory. If running unpatched firmware and web server is enabled, the system is vulnerable.Check Version:
Check firmware version via MELSOFT engineering software or web interface system information pageVerify Fix Applied:
Verify firmware version has been updated to patched version specified in vendor advisory and test web server functionality under normal and stress conditions.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP request patterns to PLC web interface
- Web server timeout or error messages in PLC logs
- Multiple failed connection attempts from single sources
Network Indicators:
- Abnormal HTTP traffic volume to PLC port 80/443
- HTTP requests with malformed length parameters
- Traffic from unauthorized IP addresses to PLC
SIEM Query:
source_ip="PLC_IP" AND (http_request contains "malformed" OR http_status="500" OR connection_count > threshold)