Local service interruption via untracked shadow writes
Published Apr 1, 2026 · Updated Apr 1, 2026
A KVM shadow-MMU flaw in Linux Kernel allows local users to interrupt service through untracked host-userspace writes. In mmu_set_spte, a sanity check assumes that a shadow-present SPTE cannot be replaced with a different target PFN, but indirect MMUs can receive host writes that bypass KVM write tracking and violate that assumption. Access to KVM from host userspace is required; the observed result is a kernel warning and availability loss, with no reported data disclosure or modification.
Summary
What happened
A KVM shadow-MMU flaw in Linux Kernel allows local users to interrupt service through untracked host-userspace writes. In mmu_set_spte, a sanity check assumes that a shadow-present SPTE cannot be replaced with a different target PFN, but indirect MMUs can receive host writes that bypass KVM write tracking and violate that assumption. Access to KVM from host userspace is required; the observed result is a kernel warning and availability loss, with no reported data disclosure or modification.
The record
- CVE
- CVE-2026-23402
- Published
- Apr 1, 2026
- Updated
- Apr 1, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 1, 2026CVE publishedPublication date reported by the CVE source.
- Apr 1, 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=11d45175111d933c5175acc28e56af2213dd5cd6 <df83746075778958954aa0460cca55f4b3fc9c02
- Affected versionversion=6.16
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
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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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