CVE-2026-80867

What it actually does

The vulnerability permits userspace to mmap PCI BARs on Alpha architecture without invoking security_locked_down(LOCKDOWN_PCI_ACCESS), allowing DMA-capable mappings even when kernel lockdown is enabled.

Why it matters to the business

Locked-down systems on affected architectures could face elevated risk of hardware-level memory access attacks, increasing potential for data exposure or privilege escalation in environments that depend on lockdown protections.

How an attack unfolds

An attacker with local access sufficient to invoke pci_mmap_resource on an Alpha Linux system bypasses the missing lockdown check, obtains direct mappings to PCI resources, and leverages them to perform DMA reads or writes against host memory.

How to fix it

Apply the kernel commit that inserts the security_locked_down(LOCKDOWN_PCI_ACCESS) check into Alpha's pci_mmap_resource function; rebuild and deploy the updated kernel image.

How to confirm the fix worked

Inspect the pci_mmap_resource implementation in kernel source for the security_locked_down call, or confirm the patched kernel version is running via uname and module verification.

Typical attack path

1. Locate Alpha-based Linux kernel without the lockdown check in pci_mmap_resource
2. Obtain local execution context capable of PCI resource mapping calls
3. Invoke mmap on PCI BAR while lockdown mode is active
4. Use resulting mapping to conduct DMA attack against system memory

How to detect it

Review kernel audit logs and dmesg for PCI BAR mapping attempts that occur while lockdown is reported active; correlate with process execution attempting direct hardware resource access.

What your security team should do

• Prioritize kernel update on any Alpha-based systems
• Audit lockdown configuration and PCI access policies across fleets
• Disable unnecessary PCI mmap capabilities where feasible