Kernel memory disclosure via invalid SSPTPTR walk
Published Nov 12, 2025 · Updated Aug 5, 2026
An IOMMU debugfs memory-safety flaw in Linux allows local users to expose kernel memory, change device state, or crash the host through a file read. domain_translation_struct_show() walks SSPTPTR when a legacy-mode context uses a translation type that ignores that pointer, so an uninitialized or zero value becomes an unchecked physical address. Reachability requires Intel VT-d, CONFIG_INTEL_IOMMU_DEBUGFS, a mounted and traversable debugfs tree, and a pass-through or identity-domain context; one read can disclose physical memory, touch side-effecting device registers, deadlock IOMMU operations, or panic the host.
Summary
What happened
An IOMMU debugfs memory-safety flaw in Linux allows local users to expose kernel memory, change device state, or crash the host through a file read. domain_translation_struct_show() walks SSPTPTR when a legacy-mode context uses a translation type that ignores that pointer, so an uninitialized or zero value becomes an unchecked physical address. Reachability requires Intel VT-d, CONFIG_INTEL_IOMMU_DEBUGFS, a mounted and traversable debugfs tree, and a pass-through or identity-domain context; one read can disclose physical memory, touch side-effecting device registers, deadlock IOMMU operations, or panic the host.
The record
- CVE
- CVE-2025-40155
- Published
- Nov 12, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 12, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 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?
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- Affected versionversion=2b437e80456654df3980706384065d444f4bb54d <d8cf7b59c49f9118fa875462e18686cb6b131bb5
- Affected versionversion=2b437e80456654df3980706384065d444f4bb54d <df2bf759a0bdb71f13e327d7527260d09facc055
- Affected versionversion=2b437e80456654df3980706384065d444f4bb54d <fbe6070c73badca726e4ff7877320e6c62339917
- Affected versionversion=6.7
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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