Incorrect TLB invalidation via negative walk-level truncation
Published Sep 16, 2026 · Updated Sep 16, 2026
Linux KVM arm64 6.16 miscalculates VNCR TLB invalidation ranges when the stage-1 MMU is disabled during nested virtualization. pgshift_level_to_ttl() casts the negative S1_MMU_DISABLED walk level to an unsigned value, considers only its low two bits, and passes a zero-size result from ttl_to_size() into range computation. The public record does not specify a practical trigger, attacker privilege, or resulting security consequence beyond incorrect invalidation behavior.
Summary
What happened
Linux KVM arm64 6.16 miscalculates VNCR TLB invalidation ranges when the stage-1 MMU is disabled during nested virtualization. pgshift_level_to_ttl() casts the negative S1_MMU_DISABLED walk level to an unsigned value, considers only its low two bits, and passes a zero-size result from ttl_to_size() into range computation. The public record does not specify a practical trigger, attacker privilege, or resulting security consequence beyond incorrect invalidation behavior.
The record
- CVE
- CVE-2026-89775
- Published
- Sep 16, 2026
- Updated
- Sep 16, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 16, 2026CVE publishedPublication date reported by the CVE source.
- Sep 16, 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=6.16
- Affected versionversion=7270cc9157f474dfc46750a34c9d7defc686b2eb <1c9fca34b9625a67a7f1a03c8604f3df760c6c49
- Affected versionversion=7270cc9157f474dfc46750a34c9d7defc686b2eb <8053393680d4fa3eb962667d2be95dd39f0940e5
- Affected versionversion=7270cc9157f474dfc46750a34c9d7defc686b2eb <be54a70067c7dbe1381157e8a238fa4b16ea9c05
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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Your stack
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