The Linux kernel's RDMA/hfi1 driver contains a logic flaw in the hfi1_free_devdata function. It assumes the device has already been inserted into the unit table and unconditionally clears dd->unit. When xa_alloc_irq() fails, the zero‑initialized unit remains at index 0, so the subsequent cleanup step can inadvertently delete an unrelated device from that slot. This unintended device removal disables RDMA functionality for the affected system and can disrupt services that rely on remote direct memory access.

The vulnerability touches the Linux kernel’s RDMA/hfi1 subsystem. No version range is specified in the data, so any kernel build that includes the existing handling logic and has not been updated with the described fix is potentially affected. Administrators should treat all unpatched Linux kernel installations as susceptible until a release that incorporates the commit restoring proper unit handling is applied.

The EPSS score of less than 1% indicates a very low probability of exploitation, and the vulnerability is not currently listed in CISA’s KEV catalogue. The flaw is limited to kernel-space execution and requires conditions that cause an allocation failure during device initialization, which is unlikely to be triggered without local or physical access. Nevertheless, the impact—removal of an RDMA device—can lead to service interruption on affected hosts. Given the low likelihood but definitive potential for denial of service, operators should be aware of the issue even if the exploit risk remains modest.