The Linux kernel vulnerability CVE-2026-90240 affected the iommu/vt-d code path where context cache flushing was performed incorrectly during the teardown of DMA aliases. Specifically, the functions domain_context_clear_one() and device_pasid_table_teardown() cleared context entries in memory but failed to invalidate the corresponding entries in the hardware context cache for aliases other than the device's own requester ID. This caused hardware to use stale cached entries referencing freed PASID directories, allowing the IOMMU to walk freed memory. The fix involved passing the correct source ID to intel_context_flush_no_pasid() to ensure proper invalidation of the context cache entries.

This vulnerability could allow an attacker with limited privileges (local) to cause the IOMMU to reference freed memory, potentially leading to memory corruption, information disclosure, or privilege escalation. The CVSS score of 8.8 reflects high impact on confidentiality, integrity, and availability.

A fix for this vulnerability is available in the Linux kernel. Users and administrators should apply the official kernel update that includes the corrected context cache flushing logic. No additional mitigation is required beyond applying the patch.