CVE-2025-40214 Siemens CVE debrief

Who should care

Linux kernel developers, Linux distribution maintainers, and users of Linux-based systems, especially those using AF_UNIX sockets, should assess exposure and verify if their systems are affected by this vulnerability. System administrators and security teams should prioritize patching or mitigating this vulnerability to prevent potential denial of service or code execution.

Why it matters

The Linux kernel vulnerability in the AF_UNIX garbage collection mechanism requires attention from Linux kernel developers, distribution maintainers, and users. The vulnerability could lead to denial of service or code execution, and its exploitation requires specific sequences of socket connections and closures. Verification and patching are essential to prevent potential impacts.

• Denial of service due to garbage collection of receive queues
• Potential execution of arbitrary code with elevated privileges
• Verification of socket connections and closures required to prevent exploitation
• Patching or mitigation efforts required to address vulnerability

Technical summary

The Linux kernel's AF_UNIX garbage collection mechanism is vulnerable to a denial of service or potential code execution due to incorrect initialization of the scc_index in the unix_add_edge function. This issue was reported by Quang Le and involves a specific sequence of socket connections and closures that could lead to the garbage collection of a receive queue of an alive in-flight socket. The vulnerability requires attention from Linux kernel developers, distribution maintainers, and users. Verification and patching are essential to prevent potential impacts. The repro consists of three stages: creating cyclic references, passing sockets, and triggering GC. An attacker could exploit this vulnerability by  

Defensive priority

High

Recommended defensive actions

• Update to the latest version of the Linux kernel
• Monitor system logs for potential exploitation attempts
• Implement additional security controls to prevent local exploitation
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The Linux kernel vulnerability was reported by Quang Le and involves the AF_UNIX garbage collection mechanism. The vulnerability is caused by the incorrect initialization of the scc_index in the unix_add_edge function. A repro consists of three stages: creating cyclic references, passing sockets, and triggering GC.

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.