CVE-2026-45862: iommu/vt-d: Flush cache for PASID table before using it
In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Flush cache for PASID table before using it
When writing the address of a freshly allocated zero-initialized PASID table to a PASID directory entry, do that after the CPU cache flush for this PASID table, not before it, to avoid the time window when this PASID table may be already used by non-coherent IOMMU hardware while its contents in RAM is still some random old data, not zero-initialized.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
In iommu/vt-d, flush the CPU cache for the PASID table before using it. Specifically, when initializing a freshly allocated zero-initialized PASID table, ensure the cache flush occurs before writing the PASID table address into the PASID directory entry, so any stale/random old data in RAM is not used during the time window.
Linux kernel (iommu/vt-d PASID table handling) Flush cache for PASID table before writing PASID table entry to PASID directory = Do the CPU cache flush before updating the PASID directory entry (write after flush; not before)