A missing decrement in the iommu_call_iopf_notifier functioned PCI device reference that is never released. The accumulation of unreleased references to PCI devices can exhaust kernel memory and trigger system instability or denial of service. The vulnerability aligns with CWE‑911, Improper Management of Resource Reference Count.

The flaw resides in the Linux kernel’s AMD IOMMU subsystem. Kernels that enable the iommu_call_iopf_notifier path, typically compiled for AMD hardware with IOMMU support, are vulnerable. All Linux kernel versions prior to the commit that added the missing drop are affected; version ranges are not explicitly listed.

The CVSS score is 4.4 and the EPSS score is below 1 %, indicating a low likelihood of widespread exploitation. The vulnerability is not listed in the CISA KEV catalog. Exploitation requires repeated PPR faults, which may be limited to privileged or hardware‑specific code, but the reference‑count leak can gradually drain kernel resources, leading to rare but potentially disruptive failures.