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CVE-2026-23558

7.8 · HIGH

The adjustments made for XSA-379 as well as those subsequently becoming XSA-387 still left a race window, when a HVM or PVH guest does a grant table version change from v2 to v1 in parallel with ma…

Published May 19, 2026CWE-362EPSS 0.12%

Overview

CVE-2026-23558 is a high-severity vulnerability. It was published on May 19, 2026 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

The adjustments made for XSA-379 as well as those subsequently becoming

XSA-387 still left a race window, when a HVM or PVH guest does a grant

table version change from v2 to v1 in parallel with mapping the status

page(s) via XENMEM_add_to_physmap. Some of the status pages may then be

freed while mappings of them would still be inserted into the guest's

secondary (P2M) page tables.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refxenbits.xenproject.org/xsa/advisory-486.htmlRefwww.openwall.com/lists/oss-security/2026/04/28/13Refxenbits.xen.org/xsa/advisory-486.html

How CyberStrike helps

Frequently asked questions

What is CVE-2026-23558?

CVE-2026-23558 is a high-severity vulnerability. It was published on May 19, 2026 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-23558?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-23558?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-23558?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-23558 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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