Xen Xenstore Bitmap state issue

Summaryinfo

A vulnerability has been found in Xen Xenstore and classified as very critical. Affected is an unknown function of the component Bitmap. The manipulation leads to state issue. This vulnerability is referenced as CVE-2026-42492. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Xen Xenstore (the affected version unknown) and classified as very critical. This issue affects an unknown part of the component Bitmap. The manipulation with an unknown input leads to a state issue vulnerability. Using CWE to declare the problem leads to CWE-371. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at xenbits.xenproject.org. The identification of this vulnerability is CVE-2026-42492 since 04/27/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/02/2026).

The vulnerability scanner Nessus provides a plugin with the ID 331597 (Fedora 44 : xen (2026-bf1da84dfc)), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (331597) and CERT Bund (WID-SEC-2026-2568). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Open Source Xen

Productinfo

Type

• Virtualization Software

Vendor

• Xen

Name

• Xenstore

License

• open-source

CPE 2.3info

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CPE 2.2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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