CVE-2025-13406 Overview
A NULL Pointer Dereference vulnerability has been identified in the Softing Industrial Automation GmbH smartLink SW-HT device, specifically within its Webserver modules. This flaw allows attackers to trigger a Denial of Service (DoS) condition via maliciously crafted HTTP requests. When exploited, the vulnerability causes the webserver to crash by dereferencing a null pointer, effectively disrupting device availability and potentially impacting industrial automation processes that depend on the smartLink SW-HT gateway.
Critical Impact
Successful exploitation can render the smartLink SW-HT webserver unavailable, disrupting industrial communication and monitoring capabilities in OT/ICS environments.
Affected Products
- Softing Industrial Automation GmbH smartLink SW-HT version 1.43
- smartLink SW-HT Webserver modules
Discovery Timeline
- 2026-03-17 - CVE CVE-2025-13406 published to NVD
- 2026-03-18 - Last updated in NVD database
Technical Details for CVE-2025-13406
Vulnerability Analysis
This vulnerability is classified as CWE-476 (NULL Pointer Dereference), a memory corruption flaw where the application attempts to use a pointer that is expected to contain a valid memory address but instead holds a null value. In the context of the smartLink SW-HT webserver modules, this condition is triggered through specific HTTP request handling, causing the server process to crash immediately upon dereferencing the invalid pointer.
The vulnerability is network-accessible, meaning remote attackers can send crafted HTTP requests to the device without requiring physical access. While the attack requires high privileges and some user interaction, successful exploitation results in high availability impact to both the vulnerable system and potentially connected downstream systems in the industrial network.
Root Cause
The root cause stems from insufficient validation of pointer values before dereferencing within the webserver module's HTTP request processing logic. When certain HTTP requests are processed, the code fails to verify that a pointer has been properly initialized before attempting to access the memory location it references. This lack of defensive programming allows an attacker-controlled input to create a condition where a null pointer is dereferenced, immediately crashing the webserver process.
Attack Vector
The attack is conducted over the network by sending specially crafted HTTP requests to the smartLink SW-HT webserver. The attacker must have high-level privileges on the target system, and some user interaction is required to successfully trigger the vulnerability. Once the malicious request is processed, the null pointer dereference occurs in the webserver module, causing an immediate denial of service condition that affects the device's availability and potentially impacts connected industrial systems.
The vulnerability does not enable data exfiltration or integrity compromise, but the availability impact extends to both the local system and potentially safety-related systems that depend on the smartLink SW-HT gateway for communication.
Detection Methods for CVE-2025-13406
Indicators of Compromise
- Unexpected webserver crashes or service restarts on smartLink SW-HT devices
- Abnormal HTTP request patterns in device logs, particularly malformed or unusual requests
- Device availability issues without clear operational cause
- Repeated crash dumps or error logs indicating null pointer exceptions
Detection Strategies
- Monitor smartLink SW-HT devices for unexpected service restarts or crashes
- Implement network-based monitoring for anomalous HTTP traffic targeting industrial devices
- Configure alerting on repeated webserver process failures
- Deploy industrial intrusion detection systems (IDS) to identify suspicious HTTP request patterns
Monitoring Recommendations
- Enable comprehensive logging on smartLink SW-HT webserver modules
- Integrate device logs with centralized SIEM for correlation analysis
- Establish baseline behavior for normal HTTP request patterns to the device
- Monitor network segments containing industrial automation devices for unusual traffic
How to Mitigate CVE-2025-13406
Immediate Actions Required
- Review network access controls to restrict HTTP access to smartLink SW-HT devices to authorized personnel only
- Implement network segmentation to isolate industrial automation devices from untrusted networks
- Monitor for suspicious HTTP traffic targeting affected devices
- Contact Softing Industrial Automation for guidance on available patches or firmware updates
Patch Information
Softing Industrial Automation has published a security advisory for this vulnerability. Administrators should consult the Softing CVE-2025-13406 Advisory for official patch information and remediation guidance. Additional technical details are available in the Softing CVE-2025-13406 JSON Details.
Workarounds
- Restrict network access to the smartLink SW-HT webserver interface using firewall rules or access control lists (ACLs)
- Place the device behind a VPN or other secure access gateway to limit exposure
- Disable the webserver module if not required for operational purposes
- Implement rate limiting on HTTP connections to the device to reduce potential exploitation attempts
# Example firewall rule to restrict HTTP access to smartLink SW-HT
# Replace <DEVICE_IP> with the actual IP address of the smartLink SW-HT
# Replace <TRUSTED_NETWORK> with authorized management network CIDR
iptables -A INPUT -d <DEVICE_IP> -p tcp --dport 80 -s <TRUSTED_NETWORK> -j ACCEPT
iptables -A INPUT -d <DEVICE_IP> -p tcp --dport 80 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
