Xen Grant Copy Cache input validation

Summaryinfo

A vulnerability, which was classified as very critical, has been found in Xen. This impacts an unknown function of the component Grant Copy Cache. The manipulation leads to input validation. This vulnerability is listed as CVE-2026-102703. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Xen (affected version unknown) and classified as very critical. This issue affects an unknown functionality of the component Grant Copy Cache. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] A common access pattern is a batch of Grant Copy operations acting on adjacent address ranges in the same source or destination page. For performance reasons, Xen caches details internally to reuse already validated data. The conditions on when to re-validate the internal data were not correct in some cases: - Frame numbers and grant references could wrongly be mixed up. This is CVE-2026-102703. - Copying by frame number (rather than grant reference) is permitted only when operating on the caller's own memory. The check to enforce this restriction was misplaced. This is CVE-2026-102704.

The advisory is shared at xenbits.xenproject.org. The identification of this vulnerability is CVE-2026-102703 since 09/29/2026. The exploitation is known to be easy. The attack may be initiated remotely. Additional levels of successful authentication are necessary for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 11/04/2026).

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

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Productinfo

Type

• Virtualization Software

Name

• Xen

License

• open-source

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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