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Vulnerability record · CVE-2026-23558 · published 19 May 2026

CVE-2026-23558: Xen race condition vulnerability

Xen · Xen

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.

7.8 CVSS 3.1 High EPSS 0.12% · top 98.5% CWE-362 · Race condition
7.8CVSS 3.1 base score
0.12%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://xenbits.xenproject.org/xsa/advisory-486.html MitigationPatchVendor Advisory
http://www.openwall.com/lists/oss-security/2026/04/28/13 Mailing ListMitigationPatchThird Party Advisory
http://xenbits.xen.org/xsa/advisory-486.html MitigationPatchVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2017-10912Xen vulnerabilityXen through 4.8.x mishandles page transfer, which allows guest OS users to obtain privileged host OS access, aka XSA-217.EPSS 2.7%10.0CVE-2017-10918Xen improper input validation vulnerabilityXen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to obtain privileged host OS access…EPSS 3.7%10.0CVE-2017-10920Xen memory buffer overflow vulnerabilityThe grant-table feature in Xen through 4.8.x mishandles a GNTMAP_device_map and GNTMAP_host_map mapping, when followed by only a GNTMAP_host_map unma…EPSS 2.5%10.0CVE-2017-10921Xen memory buffer overflow vulnerabilityThe grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and GNTMAP_host_map mapping, which allows…EPSS 2.5%10.0CVE-2015-8104Xen vulnerabilityThe KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic o…EPSS 2.5%9.9CVE-2017-2620Qemu out-of-bounds write vulnerabilityQuick emulator (QEMU) before 2.8 built with the Cirrus CLGD 54xx VGA Emulator support is vulnerable to an out-of-bounds access issue. The issue could…EPSS 3.6%9.9CVE-2018-12892Debian linux information exposure vulnerabilityAn issue was discovered in Xen 4.7 through 4.10.x. libxl fails to pass the readonly flag to qemu when setting up a SCSI disk, due to what was probabl…EPSS 2.5%9.8CVE-2025-58142Xen vulnerability[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] There are multiple i…EPSS 0.47%

Source: NIST National Vulnerability Database (record CVE-2026-23558), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.