CVE-2026-23558
Published: 19 May 2026
Summary
CVE-2026-23558 is a high-severity Race Condition (CWE-362) vulnerability in Xen Xen. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 2.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-30928
Vulnerability details
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)…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Race condition in Xen hypervisor grant/P2M handling directly enables guest-to-host privilege escalation and VM escape via memory mapping corruption.
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Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Accurate timestamps from internal clocks enable detection of race conditions by providing reliable event ordering in audit logs.
Coordination of concurrent security activities reduces the probability that shared resources will be accessed simultaneously without proper synchronization.