PCIe isolation bypass via omitted tboot ACS request
Published Sep 11, 2026 · Updated Sep 11, 2026
Security-feature bypass in affected Linux kernels allows attackers to weaken PCIe device isolation on Intel VT-d systems. The detect_intel_iommu() path omits tboot when deciding whether to call pci_request_acs(), yet tboot_force_iommu() later enables the IOMMU. Exposure requires an Intel TXT/tboot launch with ACS disabled by options or platform state, leaving PCIe peer traffic without the intended isolation and enabling DMA attacks.
Summary
What happened
Security-feature bypass in affected Linux kernels allows attackers to weaken PCIe device isolation on Intel VT-d systems. The detect_intel_iommu() path omits tboot when deciding whether to call pci_request_acs(), yet tboot_force_iommu() later enables the IOMMU. Exposure requires an Intel TXT/tboot launch with ACS disabled by options or platform state, leaving PCIe peer traffic without the intended isolation and enabling DMA attacks.
The record
- CVE
- CVE-2026-89448
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1200
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.6.33
- Affected versionversion=5d990b627537e59a3a2f039ff588a4750e9c1a6a <45705a6bfdb283f7b3b509010fd617b72f942537
- Affected versionversion=5d990b627537e59a3a2f039ff588a4750e9c1a6a <607432b2618b61df81134be0ef2562b8300c1216
- Affected versionversion=5d990b627537e59a3a2f039ff588a4750e9c1a6a <87bc611c6c98a41c00feb7b06b0c297dd141a2ae
- Affected versionversion=5d990b627537e59a3a2f039ff588a4750e9c1a6a <aaeb81241e802c86be69394f72d49fde3f861fbb
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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