Xen: Incomplete Cleanup
CVE-2026-42492 is a high-severity incomplete cleanup vulnerability in Xen, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.61% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Xen you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CISA (ADP).
Official description
Xenstore, to have an up-to-date picture of the entire system, wants to know of domains appearing and disappearing. To make this more robust, a new XEN_DOMCTL_get_domain_state was introduced. The management of the bitmap underlying that operation is tied into the binding of the VIRQ_DOM_EXC virtual IRQ. Unfortunately an error path there would tear down the bitmap even in cases when it wasn't set up. Unprivileged domains can trigger that error path.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incomplete Cleanup
The product does not properly clean up and remove temporary or supporting resources after they have been used.
How developers prevent this class of flaw
- Temporary files and other supporting resources should be deleted/released immediately after they are no longer needed.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
References
Other references
Other vulnerabilities in Xen
- 8.8 High severity
- 8.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.3 High severity
Recent Incomplete Cleanup vulnerabilities
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 9.6 Critical severity
- 8.1 High severity
- 9.8 Critical severity
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