CVE-2024-50210 Siemens CVE debrief

Who should care

Industrial control system operators, OT security teams, and organizations deploying Siemens SIMATIC S7-1500 TM MFP controllers with GNU/Linux subsystems should prioritize this vulnerability. The affected systems are commonly used in manufacturing and critical infrastructure environments where availability is paramount. System administrators responsible for embedded Linux environments and kernel maintenance should also monitor for similar posix-clock subsystem issues.

Technical summary

The pc_clock_settime() function in the Linux kernel's POSIX clock subsystem contains an unbalanced locking vulnerability. When get_clock_desc() succeeds, it acquires the clk->rwsem read lock and increments a file descriptor reference via fget(). However, certain error paths fail to release these resources, resulting in lock imbalance and reference count leaks. The vulnerability specifically manifests when timespec64_valid_strict() validation fails after lock acquisition. The remediation reorders validation to occur before get_clock_desc(), ensuring that error paths cannot leave resources in an inconsistent state. This is classified as CWE-667 (Improper Locking) with CVSS 3.1 score of 5.5 (MEDIUM), requiring local access with low privileges to exploit.

Defensive priority

medium

Recommended defensive actions

• Apply vendor-provided kernel updates for affected Siemens SIMATIC S7-1500 TM MFP systems when available
• Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
• Implement application whitelisting to ensure only trusted applications are built and executed on affected systems
• Monitor for anomalous resource consumption patterns that may indicate exploitation attempts
• Review and implement CISA ICS recommended practices for defense-in-depth strategies

Evidence notes

The vulnerability description indicates this is a Linux kernel posix-clock subsystem issue involving unbalanced locking in pc_clock_settime(). The flaw was introduced when error paths failed to release locks and file descriptor references acquired by get_clock_desc(). The fix reorders timespec64_valid_strict() validation to occur before get_clock_desc() to prevent the unbalanced state. Siemens has confirmed this affects the GNU/Linux subsystem of SIMATIC S7-1500 TM MFP industrial controllers. CISA published advisory ICSA-24-102-01 on 2024-04-09 with this CVE included in later revisions (Additional Release 6 on 2025-06-10).

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.