CVE-2026-42489

Host-wide service interruption via unfair domctl locking

Published Jun 18, 2026 · Updated Jun 18, 2026

Improper locking in Xen 3.3 and later allows local users with guest-management privileges to interrupt an entire host through domctl operations. The hypervisor serializes nonparallel guest-management requests with a system-wide lock whose acquisition path does not enforce fairness. A less-privileged control, Xenstore, or guest-controlling domain can repeatedly win the lock and starve equally or more privileged work, stalling service across the host.

CVSS severity5.3
Medium
EPSS probability0.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in Xen 3.3 and later allows local users with guest-management privileges to interrupt an entire host through domctl operations. The hypervisor serializes nonparallel guest-management requests with a system-wide lock whose acquisition path does not enforce fairness. A less-privileged control, Xenstore, or guest-controlling domain can repeatedly win the lock and starve equally or more privileged work, stalling service across the host.

The record

CVE
CVE-2026-42489
Published
Jun 18, 2026
Updated
Jun 18, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-667, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jun 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 18, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3CISA ADP VulnrichmentCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-667Improper Locking
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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