A defect in the Linux kernel’s fp9931 regulator driver leaks power‑management references when a hardware‑monitor read fails. The regmap_read error is returned without releasing the pm_runtime put autosuspend reference, causing the reference count to grow. Over time this resource exhaustion can destabilize the power‑management subsystem and lead to a denial of service. The underlying weakness is a resource‑management flaw classified as CWE‑911.

The vulnerability exists in any Linux kernel version that ships the fp9931 regulator driver without the patch commit 0902010c8d163f7b62e655efda1a843529152c7c. Systems that load this driver on a vulnerable kernel are susceptible whenever a hardware‑monitor read operation encounters an error.

The EPSS score is below 1% and the vulnerability is not listed in CISA’s KEV catalog, indicating a low probability of exploitation. The CVSS score of 5.5 suggests a medium severity. The attack requires an environment where the fp9931 register map read can repeatedly fail, which is most likely achieved by local system compromise or by inducing fault conditions in the hardware. Based on the description, the likely attack vector is local fault injection that forces repeated read errors; without such conditions the risk remains primarily maintenance‑related rather than an active attack vector.