CVE-2025-26858
📋 TL;DR
A buffer overflow vulnerability in the Modbus TCP functionality of Socomec DIRIS Digiware M-70 version 1.6.9 allows unauthenticated attackers to send specially crafted network packets, potentially causing denial of service. This affects users of the specified device version with Modbus TCP enabled. The vulnerability stems from improper input validation (CWE-20).
💻 Affected Systems
- Socomec DIRIS Digiware M-70
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash or persistent denial of service, disrupting monitoring and control functions in industrial environments.
Likely Case
Temporary denial of service, requiring device reboot to restore functionality.
If Mitigated
Minimal impact if network segmentation and access controls prevent unauthorized access to the Modbus TCP port.
🎯 Exploit Status
Exploitation involves sending crafted packets to the Modbus TCP port, which is straightforward but may require network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for updated version; likely requires upgrade beyond 1.6.9.
Vendor Advisory: https://www.socomec.fr/sites/default/files/2025-10/CVE-2025-26858---Diris-Digiware-Mxx-Dxx-_VULNERABILITIES_2025-10-01-16-38-44_English_0.pdf
Restart Required: Yes
Instructions:
1. Review vendor advisory for patched firmware version. 2. Backup device configuration. 3. Download and apply firmware update via management interface. 4. Reboot device as required. 5. Verify functionality post-update.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to Modbus TCP port (typically 502) using firewalls or network ACLs to trusted IPs only.
Disable Modbus TCP
allIf not needed, disable Modbus TCP functionality in device settings to eliminate attack surface.
🧯 If You Can't Patch
- Implement strict network access controls to limit traffic to the Modbus TCP port from authorized sources only.
- Monitor network traffic for anomalous packets targeting port 502 and set up alerts for potential exploitation attempts.
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via web interface or CLI; if version is 1.6.9 and Modbus TCP is enabled, it is vulnerable.Check Version:
Use device-specific CLI or web interface; common command may vary (e.g., 'show version' or check via management GUI).Verify Fix Applied:
After patching, confirm firmware version is updated to a patched release and test Modbus TCP functionality for stability.📡 Detection & Monitoring
Log Indicators:
- Device logs showing crashes, reboots, or errors related to Modbus TCP processing.
Network Indicators:
- Unusual traffic spikes or malformed packets on port 502 from untrusted sources.
SIEM Query:
Example: 'source_port:502 AND (packet_size > threshold OR protocol_anomaly)' adjust based on SIEM capabilities.