Technical impact
A race condition between the Linux counter (rz‑mtu3‑cnt) and PWM drivers causes the shared struct rz_mtu3_channel to hold an incorrect struct device pointer. When the counter driver performs runtime power management it may act on the wrong device instance, potentially leaving a device in an unintended power state or triggering kernel instability. The weakness is a misuse of shared data structures (CWE-820).
Affected Systems
Linux kernel builds that load both the counter and PWM drivers. The affected kernel versions are listed in the supplied CPE strings, including Linux kernel 7.0 release candidates 1 through 6; any other kernel containing these drivers may also be impacted.
Risk and Exploitability
The CVSS score of 5.5 indicates medium severity, while the EPSS score of less than 1% indicates a very low likelihood of exploitation. The flaw is not listed in CISA’s KEV catalog and no public exploits have been disclosed. Because the issue is limited to kernel internal driver coordination, only a local attacker that can influence the loading order of these drivers would be able to trigger it. No remote exploitation pathway is described in the available data.
Ubuntu USN