In the Linux kernel’s sunrpc module, the /proc/net/rpc/use-gss-proxy file is created before the sn->gssp_lock mutex is initialized. During this brief window a user‑initiated write can trigger a lock on a zero‑initialized mutex, leading to a race condition (CWE‑909) that may allow multiple writers to leak GSS client handles or cause a denial of service. This weakness requires local access and relies on preemption to trigger the race; it does not enable remote code execution or privilege escalation.

All Linux kernel deployments that include the sunrpc module are potentially affected. Because the vulnerable ordering between proc entry creation and mutex initialization existed in every kernel prior to the fix, any unpatched kernel version, regardless of distribution, can be impacted. No specific version numbers are provided, so the vulnerability applies to all kernels shipped before the commit that moved the mutex initialization into sunrpc_init_net.

The CVSS base score of 4.1 indicates a moderate severity. The EPSS score of 0.001 indicates a very low but nonzero likelihood that the flaw will be actively exploited. The vulnerability is not in the CISA KEV catalog. precise timing widespread exploitation is unlikely but not impossible. The race condition on the uninitialized sn->gssp_lock mutex (CWE‑909) may allow multiple writers to leak GSS client handles or cause a denial of service, so immediate patching or mitigation is advised.