Guest execute-permission bypass via incorrect XN bit clearing
Published Jun 25, 2026 · Updated Jun 25, 2026
Improper permission handling in arm64 KVM in Linux Kernel 6.19 allows local users to bypass XN enforcement via nested guest mappings. In arch/arm64/include/asm/kvm_nested.h, FIELD_PREP is applied to an XN value already extracted from its bitfield, so clearing XN[0] instead grants execute permission. Reachability requires arm64 nested virtualization on hardware without FEAT_XNX; the published record does not establish a host escape.
Summary
What happened
Improper permission handling in arm64 KVM in Linux Kernel 6.19 allows local users to bypass XN enforcement via nested guest mappings. In arch/arm64/include/asm/kvm_nested.h, FIELD_PREP is applied to an XN value already extracted from its bitfield, so clearing XN[0] instead grants execute permission. Reachability requires arm64 nested virtualization on hardware without FEAT_XNX; the published record does not establish a host escape.
The record
- CVE
- CVE-2026-53200
- Published
- Jun 25, 2026
- Updated
- Jun 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 25, 2026CVE publishedPublication date reported by the CVE source.
- Jun 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=6.19
- Affected versionversion=d93febe2ed2e0491af9d47f0ee6d4b01918877f4 <49b32ddb87a3a109afecea89e55d70f73956b8bc
- Affected versionversion=d93febe2ed2e0491af9d47f0ee6d4b01918877f4 <b95976c2ea446044553a5f469c0bae13553d75ab
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What is affected?
Published CVSS scores
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Attacks
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Technologies
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Your stack
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