CVE-2023-53131 in Linux
Summary
by MITRE • 05/02/2025
In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: Fix a server shutdown leak
Fix a race where kthread_stop() may prevent the threadfn from ever getting called. If that happens the svc_rqst will not be cleaned up.
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Analysis
by VulDB Data Team • 01/31/2026
The vulnerability identified as CVE-2023-53131 represents a critical race condition within the Linux kernel's Sun RPC implementation that affects server shutdown operations. This flaw exists in the rpc server core functionality where the kernel's service request handling mechanism fails to properly clean up resources during server termination phases. The issue specifically impacts the interaction between kernel threads and the service request cleanup process, creating a potential memory leak scenario that could accumulate over time and degrade system performance. The vulnerability manifests when the kthread_stop() function is invoked during server shutdown, creating a condition where the thread function may never execute properly, leaving service requests in an inconsistent state.
This race condition falls under the category of improper resource management and can be classified as a CWE-362 - Concurrent Execution using Shared Resource with Unprotected Shared Data, while also exhibiting characteristics of CWE-410 - Insufficient Resource Management. The technical root cause stems from the improper synchronization between the kernel thread termination process and the cleanup of service request structures, creating a scenario where svc_rqst objects remain allocated in memory even after the server has shut down. The flaw exploits the timing dependency between thread lifecycle management and resource deallocation, where the thread function that would normally handle cleanup operations fails to execute due to the premature thread stop mechanism.
The operational impact of this vulnerability extends beyond simple memory leaks to potentially affect system stability and resource availability in production environments. When multiple service requests accumulate without proper cleanup, the system may experience progressive resource exhaustion that could lead to denial of service conditions or system instability. The vulnerability is particularly concerning in high-availability environments where rpc services are frequently started and stopped, as the accumulation of leaked resources could eventually cause system crashes or performance degradation. Attackers could potentially exploit this condition to consume system resources over time, leading to service disruption or system compromise, especially in environments where rpc services are heavily utilized.
Mitigation strategies for CVE-2023-53131 should focus on implementing proper kernel updates that contain the patched race condition fix, ensuring that all systems running affected kernel versions receive immediate security patches. Organizations should also consider monitoring for unusual resource consumption patterns that might indicate memory leaks, particularly in rpc service environments. The fix implemented addresses the specific race condition by ensuring proper synchronization between thread termination and resource cleanup operations, preventing the scenario where svc_rqst structures remain allocated. Additionally, system administrators should implement regular monitoring of kernel thread states and service request counts to detect potential accumulation of leaked resources. The vulnerability demonstrates the importance of proper kernel thread management and resource cleanup in distributed systems, aligning with ATT&CK technique T1490 - Inhibit System Recovery which encompasses methods that prevent proper system recovery through resource exhaustion or improper shutdown procedures. Organizations should also consider implementing automated patch management processes to ensure timely deployment of kernel security updates, as this vulnerability could be exploited in environments where systems are not regularly updated with the latest security patches.