A flaw in the Linux kernel blktrace subsystem uses the per‑CPU helpers __this_cpu_read() and __this_cpu_write() while preemption is enabled. These helpers are only safe in scheduler context, and their use in process context triggers a BUG that can lead to a kernel panic. This vulnerability does not provide an information disclosure or code execution path; its primary impact is a loss of availability by crashing the kernel. The weakness corresponds to data‑structure integrity failure (CWE-820).

All Linux kernel releases compiled with the default blktrace configuration that predate the patch are affected. The fix was demonstrated in kernel 7.0.0‑rc1 and earlier, but the issue applies to any kernel version that still contains the unguarded __this_cpu_read/write calls inside the blktrace tracing paths. No specific distribution or vendor is singled out; the problem exists in the upstream Linux kernel itself.

The CVSS score of 5.5 indicates moderate severity, while the EPSS score of less than 1% suggests a low likelihood of exploitation. The vulnerability is not listed in the CISA KEV catalog. The most likely exploitation path involves a local or privileged user performing block operations such as dd or using blk‑trace tools, which invoke blk_add_trace from process context with preemption enabled. Triggering the BUG can cause the kernel to panic, resulting in an outage. No remote exploitation or privilege escalation barrier is known from the provided data.