During the early stages of system boot, multiple udev threads may concurrently invoke the i2c‑i801 ACPI I/O handler. One thread marks a hardware region as reserved and triggers its deregistration; a second thread enters the handler after deregistration but before a safety check can confirm it. Because the handler relies on lock operations that are no longer present, a NULL‑pointer dereference occurs, resulting in a kernel panic. This flaw is a race condition (CWE‑367) that leads to an immediate system crash, effectively denying availability until a reboot is performed.

The vulnerability exists in the i2c‑i801 driver of the Linux kernel. Any Linux kernel build that contains the affected commit sequence prior to the revert commit f707d6b9e7c18f669adfdb443906d46cfbaaa0c1 is susceptible. The issue affects all distributions shipping a kernel that has not applied the fix, regardless of vendor.

The CVSS base score of 5.5 reflects moderate severity, and the EPSS score of less than 1% indicates a low likelihood of exploitation. The flaw can only be triggered on the local system during boot, when udev processes are active, and requires that the vulnerable kernel image be booted. No public exploits have been reported and the vulnerability is not listed in the CISA KEV catalog. Consequently, the primary risk is a denial‑of‑service through a kernel crash that requires a system reboot to recover.