CVE-2026-45944

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue exists in the iommu/vt-d component where tearing down a context entry involves zeroing a 128-bit entry using multiple 64-bit writes. This process can create a window where hardware fetches a torn entry, meaning some fields are zeroed while the Present bit remains set, potentially causing unpredictable behavior or spurious faults. This occurs because the compiler may reorder writes to the 64-bit halves, and hardware fetches are not guaranteed to be atomic relative to multiple CPU writes. The fix involves implementing an ownership handshake by clearing the Present bit first, using dma wmb() to ensure visibility to the IOMMU, performing cache and context-cache invalidation, and finally zeroing the entry. Additionally, dma wmb() is added to the context set present() function to ensure full initialization before the Present bit is visible.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.