The kernel’s PCI MMAP routine for Alpha processors omitted a check for the system lock‑down flag before allowing userspace processes to map PCI Base Address Registers (BARs). This oversight lets a process map PCI memory regions without confirming it has permission to do so, potentially exposing device registers and memory to unprivileged code. The weakness is a missing authorization guard that could be exploited for data disclosure or further privilege escalation, especially if the kernel has been locked down for security reasons.

All Linux kernels running on Alpha hardware are affected, including any kernel versions that do not contain the patch adding a security_locked_down(LOCKDOWN_PCI_ACCESS) guard to pci_mmap_resource(). The vulnerability applies to the generic kernel and Alpha-specific components.

Because the vulnerability relies on mapping unrestricted PCI BARs, an attacker who can run code with kernel privileges or who can achieve the lock‑down condition will have a straightforward path to manipulate device memory. The lack of a public exploit reference and the absence of an EPSS score suggest that the immediate exploitation likelihood is uncertain, but the potential impact of unauthorized memory mapping is high. The vulnerability is not currently listed in the CISA KEV catalog and no official exploit is publicly documented.