The Linux kernel’s ftrace subsystem has a race condition in the trace_parser structure. When a trace file descriptor is shared across multiple threads, concurrent writes or releases can modify the parser’s internal fields, corrupting input or producing undefined behavior. This flaw can destabilize the kernel, potentially leading to system crashes or denial of service. The weakness is a classic race condition that compromises data integrity and reliability.

All Linux kernel versions that include the vulnerable ftrace implementation and lack the guard added in the recent patch are affected. The vulnerability is mitigated by the introduction of a global mutex (parser_lock) that serializes access to trace_parser across open, write, and release operations. Specific workaround or product versions are not listed in the CNA data, so any kernel not patched for this change remains vulnerable.

The CVSS score is 5.3 and the EPSS score is less than 1%, indicating a medium severity vulnerability with a low likelihood of exploitation. The vulnerability is not listed in the CISA KEV catalog, indicating it is not a known exploited flaw. The likely attack vector is a userspace process that opens a trace file descriptor and shares it among multiple threads, triggering concurrent parser access. While the flaw can cause catastrophic corruption, no direct privilege escalation or data exfiltration is described. The risk is considered moderate; the absence of known exploits and KEV listing reduces urgency, but the internal nature of the bug means any affected system could experience instability if left unpatched.