{"apiVersion":"1.0","identifier":"CVE-2026-74439","description":"In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Clear Present bit before tearing down scalable-mode context entry device_pasid_table_teardown() zeroes the 128-bit scalable-mode context entry with context_clear_entry() while the Present bit is still set. This creates a window where the hardware can fetch a torn entry, with some fields already zeroed while Present is still set, leading to unpredictable behavior or spurious faults. The context-cache invalidation is issued only after the entry has been zeroed, and intel_pasid_free_table() then frees the PASID directory pages, so the IOMMU can keep walking a stale Present=1 entry that points at freed memory. While x86 provides strong write ordering, the compiler may reorder the two 64-bit writes to the entry, and the hardware fetch is not guaranteed to be atomic with respect to multiple CPU writes. Commit c1e4f1dccbe9d (-iommu/vt-d: Clear Present bit before tearing down context entry-) fixed this exact pattern in domain_context_clear_one() and the copied-context path, but device_pasid_table_teardown() was not converted. Align it with the -Guidance to Software for Invalidations- in the VT-d spec, Section 6.5.3.3, using the same ownership handshake as the sibling fix: clear only the Present bit, flush it to the IOMMU, perform the context-cache invalidation, and only then zero the rest of the entry.","publishedAt":"2026-08-15T06:22:46","lastModifiedAt":"2026-08-17T06:19:39","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74439","cvssScore":9.3,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","epssProbability":0.00134,"riskScore":0.94,"affectedProduct":"Linux kernel","affectedVersions":"unknown","vulnerabilityType":"Kernel","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-74439","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-74439","en":"https://www.redsauce.net/en/cves/CVE-2026-74439","fr":"https://www.redsauce.net/fr/cves/CVE-2026-74439","pt":"https://www.redsauce.net/pt/cves/CVE-2026-74439","de":"https://www.redsauce.net/de/cves/CVE-2026-74439","sk":"https://www.redsauce.net/sk/cves/CVE-2026-74439","el":"https://www.redsauce.net/el/cves/CVE-2026-74439"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-74439"}}