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CVE-2026-74439: Linux

9.3

CVSS 3.1

Няма данни

Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

Няма потвърждение

Атакува се

Няма данни

Време до експлоатация

Атакува се локално, без особени условия, без вход и без действие от потребителя.

  • Експлоатация: няма данни за експлоатация
  • Атаката не може да се автоматизира

Описание

Оригинално описание

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.

Засегнати продукти

  • Linux Linux: 81e921fd321614c2ad8ac333b041aae1da7a1c6d преди e9e83bcfe37dc719182500dd823c03ab57d934f0; 81e921fd321614c2ad8ac333b041aae1da7a1c6d преди 588718101e8449605f1c7e858fecb7cfa701cdab; 81e921fd321614c2ad8ac333b041aae1da7a1c6d преди 7fd4077dc92b91b1b844333c0a06bb9e286db10a; 81e921fd321614c2ad8ac333b041aae1da7a1c6d преди f46452c3df7a8d8a5addc0926e76ef19ea7da0a0; 333fe86968482ca701c609af590003bcea450e8f; 6.8.2 преди 6.9
  • Linux Linux: 6.9; преди 6.9; 6.12.97 до 6.12.*; 6.18.40 до 6.18.*; 7.1.5 до 7.1.*; от 7.2 нататък

История

  • 15 август 2026 Публикувано

Други уязвимости в Linux Linux

Първоизточници

CVE-2026-74439: Linux | freedomonline.bg