CVE-2026-23558
Last modified
CVE-2026-23558 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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.. EPSS estimates a 0.12% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Xen | Xen | >= 4.0.0 |
References
- https://xenbits.xenproject.org/xsa/advisory-486.htmlMitigation, Patch, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2026/04/28/13Mailing List, Mitigation, Patch, Third Party Advisory
- http://xenbits.xen.org/xsa/advisory-486.htmlMitigation, Patch, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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