Linux Kernel up to 6.12.96/6.18.39/7.1.4 iommu/vt-d device_pasid_table_teardown race condition

CVSS Meta Temp Score
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CTI Interest Score
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8.4$0-$5k0.48

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.12.96/6.18.39/7.1.4 and classified as very critical. This vulnerability affects the function device_pasid_table_teardown of the component iommu/vt-d. Performing a manipulation results in race condition. This vulnerability was named CVE-2026-74439. The attack needs to be approached locally. There is no available exploit.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 6.12.96/6.18.39/7.1.4. This affects the function device_pasid_table_teardown of the component iommu/vt-d. The manipulation with an unknown input leads to a race condition vulnerability. CWE is classifying the issue as CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-74439 since 08/15/2026. The exploitability is told to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 6.12.97, 6.18.40, 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch e9e83bcfe37dc719182500dd823c03ab57d934f0/588718101e8449605f1c7e858fecb7cfa701cdab/7fd4077dc92b91b1b844333c0a06bb9e286db10a/f46452c3df7a8d8a5addc0926e76ef19ea7da0a0 is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.97/6.18.40/7.1.5/7.2-rc1
Patch: e9e83bcfe37dc719182500dd823c03ab57d934f0/588718101e8449605f1c7e858fecb7cfa701cdab/7fd4077dc92b91b1b844333c0a06bb9e286db10a/f46452c3df7a8d8a5addc0926e76ef19ea7da0a0

Timelineinfo

08/15/2026 Advisory disclosed
08/15/2026 +0 days CVE reserved
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74439 (🔒)
GCVE (CVE): GCVE-0-2026-74439
GCVE (VulDB): GCVE-100-390393

Entryinfo

Created: 08/15/2026 10:48
Changes: 08/15/2026 10:48 (59)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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