The vulnerability arises from a missing cleanup path in the Linux kernel's IOMMU mock device code. When the mock device's device_add operation fails, the code frees only the firmware specification structure but leaves the device's IOMMU data structure allocated. Because the leaked object remains undisposed, kernel memory usage inflates with each failure. Repeated failures can therefore consume kernel memory until allocation failures occur, potentially leading to denial‑of‑service or system instability.

Vulnerable kernels that include the iommu_mock_device_add function (drivers/iommu/iommu.c) and enable the IOMMU mock subsystem are affected. The advisory does not specify exact version numbers, so any kernel build before the fix that loads this code and allows the mock interface to be exercised is at risk. Systems that use the IOMMU self‑test ioctl or other paths that trigger device_add on the mock adapter would be impacted.

The CVSS score of 5.5 indicates a moderate risk, while the EPSS score of less than 1% shows a very low probability of exploitation, and the vulnerability is not in the CISA KEV catalog. The likely attack vector is a privileged local ioctl call to the IOMMU mock device self‑test interface. Based on the description, it is inferred that an attacker who can execute the ioctl repeatedly can trigger the memory leak, leading to gradual kernel memory exhaustion and potential denial of service. Consequently, while exploitation is unlikely to be widespread, the cumulative effect could degrade system availability if the kernel is subjected to repeated failures.