The Linux kernel contains a flaw in the RISC‑V memory‑management code where an unconditional sfence.vma instruction is executed after clearing a hardware bit. If the corresponding page has not yet become valid, the system may fault again and crash. The bug can lead to a kernel panic, causing an interruption of normal operation and loss of availability for the affected machine.

All Linux kernel builds that run on RISC‑V hardware prior to the adoption of the fix are affected. No specific kernel version range is listed, so the vulnerability applies to the kernel until the commit that adds the additional guard is incorporated.

The vulnerability requires execution of privileged kernel code and is not remotely exploitable; an attacker would need to influence the kernel’s normal flow during a context switch. No CVSS score or EPSS data is available, and the issue is not listed in CISA’s KEV catalog, indicating limited exploitation evidence to date. Nonetheless, a crash is destructive, so the risk of availability impact remains non‑trivial for environments that must avoid unscheduled downtime.