A vulnerability in the Linux kernel on x86 platforms causes certain per‑CPU address loads, performed by BPF programs, to be encoded with an incorrect REX prefix. The destination register receives an unintended value, so the kernel attempts to dereference an address that was not properly converted to a per‑CPU pointer. This results in a page fault and a kernel panic, which manifests as a denial‑of‑service condition that crashes the whole system. The weakness is a null‑pointer/dereference error, identified as CWE‑476.

The flaw affects all Linux kernel implementations running on x86 hardware that have not yet applied the patch commits referenced in the advisory. Any such kernel, regardless of distribution or version, remains vulnerable until the kernel update is installed.

The CVSS score of 5.5 indicates a moderate severity level. The EPSS score is less than 1 %, suggesting a low probability of exploitation at the time of this analysis, and the flaw is not listed in the CISA KEV catalog. The likely attack vector requires the capability to load or modify BPF bytecode on the host, which normally requires elevated privileges. An attacker who can influence BPF program selection can trigger a kernel panic, causing a system‑wide denial of service. Because the fault arises during internal per‑CPU address resolution, the exploit does not rely on external network input.