The vulnerability arises in the Linux kernel’s handling of threaded busypoll, where the outer poll loop incorrectly resets timing values for RCU grace periods. This mismanagement causes the kernel’s rcu_tasks subsystem to repeatedly detect stalls, eventually leading the entire system to hang or become unresponsive. Once the hang occurs, normal user processes can no longer run and the system may require a reboot, resulting in significant downtime and data loss for affected workloads.

All Linux kernel releases prior to the commit that adds the corrected handling in napi_threaded_poll. The issue affects any system that enables threaded busypoll, which may be common on high‑performance NIC drivers or in environments using extensive network traffic polling.

The exploitability of this flaw appears to depend on enabling threaded busypoll, a kernel configuration, but the description does not explicitly state whether privileged access is required, so the attack surface is uncertain. No public exploits have been reported and the EPSS score is not available, while the vulnerability is not listed in CISA’s KEV catalog. Nevertheless, the impact is severe because a single active instance of the bug can stall the entire kernel, producing a denial‑of‑service condition. Due to the lack of known widespread exploitation, the immediate threat level is moderate but the potential damage warrants rapid remediation. The CVSS score is 5.5.