Vulnerability Snapshot
CVE-2026-74439 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.
Executive Summary
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 pa
Why It Matters
CVE-2026-74439 is rated CRITICAL severity, requiring immediate attention from security teams.
CVSS Base Score: 9.3/10
🛡️What Defenders Should Check
Use Vulnios to continuously monitor your exposure to CVE-2026-74439 and similar vulnerabilities.
References & Sources
How Vulnios Detects This
Vulnios scans for this vulnerability using Trivy and Grype for SBOM-based CVE matching and Vulnios CVE feed continuous monitoring against your asset inventory. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.
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Sources
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Frequently Asked Questions
What is CVE-2026-74439?
CVE-2026-74439 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. 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 sca
Am I affected?
Affected technology is listed in the Affected Products section above. If your asset inventory contains any of them, assume in-scope until you can prove otherwise.
How urgent is the response?
Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.
How do I remediate?
Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.
Where can I track exploitation activity?
Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2026-74439. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.
How does Vulnios help with this?
Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.
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