Host memory access via stale PASID context
Published Aug 15, 2026 · Updated Aug 15, 2026
Use-after-free in the Linux Intel VT-d PASID teardown path allows physically proximate attackers to read or write host memory. device_pasid_table_teardown() zeroes a 128-bit scalable-mode context entry while its Present bit remains set, then invalidates the context cache and frees PASID directory pages, allowing the IOMMU to fetch a torn entry or walk freed memory. Exploitation requires a PASID-capable PCIe device and a local teardown event such as physical hot-unplug while DMA remains active; consequences include cross-boundary memory access, spurious faults, hangs, or a host panic.
Summary
What happened
Use-after-free in the Linux Intel VT-d PASID teardown path allows physically proximate attackers to read or write host memory. device_pasid_table_teardown() zeroes a 128-bit scalable-mode context entry while its Present bit remains set, then invalidates the context cache and frees PASID directory pages, allowing the IOMMU to fetch a torn entry or walk freed memory. Exploitation requires a PASID-capable PCIe device and a local teardown event such as physical hot-unplug while DMA remains active; consequences include cross-boundary memory access, spurious faults, hangs, or a host panic.
The record
- CVE
- CVE-2026-74439
- Published
- Aug 15, 2026
- Updated
- Aug 15, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1200
- Attack vector
- physical
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 15, 2026CVE publishedPublication date reported by the CVE source.
- Aug 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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- Affected versionversion=333fe86968482ca701c609af590003bcea450e8f
- Affected versionversion=6.8.2 <6.9
- Affected versionversion=6.9
- Affected versionversion=81e921fd321614c2ad8ac333b041aae1da7a1c6d <588718101e8449605f1c7e858fecb7cfa701cdab
- Affected versionversion=81e921fd321614c2ad8ac333b041aae1da7a1c6d <7fd4077dc92b91b1b844333c0a06bb9e286db10a
- Affected versionversion=81e921fd321614c2ad8ac333b041aae1da7a1c6d <e9e83bcfe37dc719182500dd823c03ab57d934f0
- Affected versionversion=81e921fd321614c2ad8ac333b041aae1da7a1c6d <f46452c3df7a8d8a5addc0926e76ef19ea7da0a0
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Attacks
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Technologies
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