A flaw in the Linux kernel’s PMBus core allows an out‑of‑bounds write when probing hardware that reports more than ten phases. The driver allocates a buffer for a limited number of phases but does not validate the hardware‑reported count, resulting in data being written beyond the allocated space. This memory corruption can overwrite kernel memory, potentially causing system instability or failure.

Linux kernels that have not yet applied the patch to increase the maximum supported phase count to sixteen are affected. The mp2975 driver already supports up to fourteen phases and the mp2856 driver up to twelve, which means any system running a vulnerable kernel and connected to a PMBus device that advertises a phase count above ten is at risk. All Linux distributions containing the vulnerable kernel release are potentially impacted.

The EPSS score is less than 1 % and the vulnerability is not listed in the CISA KEV catalog. The CVSS score is 5.5, indicating medium severity. Exploitation would require the adversary to trigger a probe of an offending PMBus device, meaning a local or privileged attacker with access to the device or the ability to load the driver would be necessary. The description does not indicate any remote exploitation vector; the available evidence points to kernel memory corruption that could lead to crash or data corruption rather than immediate arbitrary code execution.