Xen Grant Table GNTTABOP_cache_flush integer underflow

Summaryinfo

A vulnerability identified as very critical has been detected in Xen. This vulnerability affects the function GNTTABOP_cache_flush of the component Grant Table. Performing a manipulation results in integer underflow. This vulnerability was named CVE-2026-102702. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Xen (affected version not known). This affects the function GNTTABOP_cache_flush of the component Grant Table. The manipulation with an unknown input leads to a integer underflow vulnerability. CWE is classifying the issue as CWE-191. The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. This is going to have an impact on 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.] 1) XSA-437 (CVE-2023-34321) addressed issues with overflows in calculations involved in guests flushing caches through GNTTABOP_cache_flush. Unfortunately the fix there introduced a calculation which may underflow, resulting in a loop which would - at least on 64-bit Arm - take excessively long, and which would likely eventually crash the hypervisor. This is CVE-2026-102699. 2) GNTTABOP_cache_flush may be issued on memory mapped from another domain using the grant table interface. However there was no restriction to disallow the use of invalidate-without-clean against read-only grant mappings, which may corrupt the granted memory. This is CVE-2026-102702.

It is possible to read the advisory at xenbits.xenproject.org. This vulnerability is uniquely identified as CVE-2026-102702 since 09/29/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/13/2026).

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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