CVE-2026-1627 identifies a cryptographic vulnerability in the SICK LMS1000 industrial sensor device, specifically in its SSH service implementation. The device uses outdated and weak Message Authentication Code (MAC) algorithms, which are cryptographic primitives designed to ensure data integrity and authenticity of SSH sessions. Weak MAC algorithms can be susceptible to cryptanalysis or collision attacks, enabling an attacker who can observe or manipulate network traffic to alter the transmitted data without detection. This compromises the integrity of the SSH session, potentially allowing injection or modification of commands or data exchanged between the client and the device. The vulnerability does not affect confidentiality directly, as encryption remains intact, but the integrity breach can lead to unauthorized control or disruption of device operations. Exploitation requires the attacker to have network access to the SSH communication path and to trick a user into initiating the session (user interaction). No authentication is required, increasing the attack surface. The CVSS v3.1 base score of 6.5 reflects a medium severity, considering the network attack vector, low attack complexity, no privileges required, but user interaction needed, and the impact limited to integrity. No patches or mitigations have been officially released by SICK AG as of the publication date. The vulnerability falls under CWE-327, which concerns the use of broken or risky cryptographic algorithms, a common issue in embedded and industrial control systems where legacy protocols or configurations persist. This vulnerability underscores the importance of updating cryptographic components in industrial devices to maintain secure communications.

The primary impact of this vulnerability is the potential compromise of data integrity within SSH sessions to the SICK LMS1000 device. An attacker capable of intercepting network traffic could manipulate commands or data sent to the device, potentially causing unauthorized actions, operational disruptions, or safety risks in industrial environments where these sensors are deployed. While confidentiality is not directly affected, integrity breaches can lead to loss of trust in device communications and may facilitate further attacks or unauthorized control. Organizations relying on these devices for critical sensing or automation tasks could face operational downtime, safety incidents, or data corruption. The lack of authentication requirement and low attack complexity increase the risk, especially in environments with exposed or poorly segmented networks. However, the need for user interaction limits automated exploitation. No known exploits in the wild reduce immediate risk but do not eliminate the threat. The medium severity rating suggests that while the vulnerability is serious, it is not critical, but it should be addressed promptly to avoid escalation or chaining with other vulnerabilities.

1. Network Segmentation: Isolate SICK LMS1000 devices on dedicated, secure network segments with strict access controls to limit exposure of SSH services to untrusted networks. 2. Use VPN or Encrypted Tunnels: Where possible, encapsulate SSH traffic within secure VPN tunnels or other encrypted channels that provide stronger integrity protections than the device’s native SSH implementation. 3. Disable SSH if Not Required: If SSH access is not necessary for device operation or maintenance, disable the SSH service entirely to eliminate the attack vector. 4. Monitor Network Traffic: Implement intrusion detection systems (IDS) or anomaly detection to identify unusual SSH session manipulations or network traffic patterns indicative of exploitation attempts. 5. Vendor Engagement: Engage with SICK AG for updates or patches addressing the weak MAC algorithm usage and apply them promptly once available. 6. User Training: Educate users on the risks of interacting with untrusted networks or initiating SSH sessions to vulnerable devices without proper safeguards. 7. Configuration Review: Review device configurations to disable legacy or weak cryptographic algorithms if configurable, replacing them with stronger, modern MAC algorithms. 8. Incident Response Planning: Prepare response plans for potential integrity compromise scenarios involving these devices to minimize operational impact.