# CVE-2026-62428: Xen grant-table type confusion in grant-copy

Source: https://junglewise.ai/threats/cve-2026-62428-xen-grant-table-type-confusion-in-grant-copy  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-28. Updated: 2026-07-28  
License: CC BY 4.0 with a link back

CVE-2026-62428 · Severity: info · CVSS 8.8 · Published 2026-07-28

A vulnerability exists in the Xen hypervisor, which is software used to run multiple virtual machines on a single physical server. An attacker operating a guest virtual machine could exploit a flaw in how the system manages shared memory to gain unauthorized access to the host server. This could lead to a complete takeover of the physical server, theft of data from other virtual machines, or a total service outage.

Technologies: [Xen Project Xen](https://junglewise.ai/threats/technologies/xen). Vendors: [Xen Project](https://junglewise.ai/threats/vendors/xen-project).

## Quick answers

**Is CVE-2026-62428 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-62428 being exploited in the wild.

**How severe is CVE-2026-62428?** Informational severity, with a CVSS score of 8.8, published 28 July 2026.

**Which products and versions are affected?** Xen Project Xen 4.2 through 4.18.x.

**Is there a fix for CVE-2026-62428?** A patch was published on 2026-07-28. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-62428 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-62428?** Check whether you run Xen Project Xen at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A type confusion vulnerability exists in Xen's grant-copy operations within the grant table implementation. When a grant-copy operation is initiated on a grant that is already 'pinned' by another active operation (such as a mapping or another copy), the hypervisor may fail to maintain consistency between the page used for permission checks and the page used for the actual copy operation. Specifically, the permission check may be performed on one guest frame while the copy is executed on a different one. An unprivileged guest can exploit this race-like inconsistency to bypass memory protections, leading to host privilege escalation, information disclosure, or a denial of service. The vulnerability affects Xen versions 4.2 onwards, provided CONFIG_GRANT_TABLE is enabled. Patches are available for stable branches including 4.17.x and 4.18.x.

## Affected products

- Xen Project Xen 4.2 through 4.18.x

## Timeline

- 2026-07-28: disclosed
- 2026-07-28: advisory
- 2026-07-28: patched

## References

- [https://xenbits.xenproject.org/xsa/advisory-500.html](https://xenbits.xenproject.org/xsa/advisory-500.html)

## Related threats

- [Xen arbitrary read/write via grant copy caching](https://junglewise.ai/threats/cve-2026-102704-this-cna-information-record-relates-to-multiple-cves-the-text)
- [Xen hypervisor arbitrary read/write via grant copy](https://junglewise.ai/threats/cve-2026-102703-this-cna-information-record-relates-to-multiple-cves-the-text)
- [Xen VMX VMentry failure with branch tracing and blocked states](https://junglewise.ai/threats/cve-2026-79611-for-xsa-308-logic-was-introduced-as-vmx-vmentry-checks-do-not)
- [Xen XPTI privilege escalation on huge-memory systems](https://junglewise.ai/threats/cve-2026-79609-xpti-xen-page-table-isolation-was-introduced-to-mitigate-meltdown)
- [Xen ineffectual Zenbleed workaround on AMD x86](https://junglewise.ai/threats/cve-2026-79608-the-workaround-for-xsa-433-zenbleed-was-later-re-worked-to-better)