CVE-2026-23558

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.

PUBLISHED Reserved 2026-01-14 | Published 2026-05-19 | Updated 2026-05-20 | Assigner XEN

Product status

Credits

This issue was discovered by Claude Opus 4.6 and diagnosed as a security issue by Rafal Wojtczuk. finder

References

www.openwall.com/lists/oss-security/2026/04/28/13

xenbits.xen.org/xsa/advisory-486.html

xenbits.xenproject.org/xsa/advisory-486.html

cve.org (CVE-2026-23558)

nvd.nist.gov (CVE-2026-23558)

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