Host denial of service via preauthorization domctl locking
Published Jun 18, 2026 · Updated Jun 18, 2026
Improper locking in Xen 3.3 and later allows guest OS users to interrupt an entire host through unauthorized domctl operations. The domctl path acquires a system-wide lock before XSM/Flask permission checks, allowing a disallowed operation to hold the lock while privileged management waits. XSM/Flask must be enabled, and the attacker must control a domain capable of submitting a relevant request; successful abuse stalls peer or privileged operations and can deny service across the host.
Summary
What happened
Improper locking in Xen 3.3 and later allows guest OS users to interrupt an entire host through unauthorized domctl operations. The domctl path acquires a system-wide lock before XSM/Flask permission checks, allowing a disallowed operation to hold the lock while privileged management waits. XSM/Flask must be enabled, and the attacker must control a domain capable of submitting a relevant request; successful abuse stalls peer or privileged operations and can deny service across the host.
The record
- CVE
- CVE-2026-42490
- Published
- Jun 18, 2026
- Updated
- Jun 18, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-667, T1499
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 18, 2026CVE publishedPublication date reported by the CVE source.
- Jun 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
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Public exploit references
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Technologies
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