# CVE-2026-23558: xen: The adjustments made for XSA-379 as well as those subsequently becoming XSA-387 still left a race window, when a HVM...

CVE-2026-23558 is fixed in xen on 1 platform, first by DEBIAN-CVE-2026-23558, released May 19, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-23558
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0012
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 19, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | xen Debian 12.15 (bookworm) | 4.17.7-0+deb12u1 | [DEBIAN-CVE-2026-23558](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23558.md) | May 19, 2026 |
| Linux | xen Debian 13.5 (trixie) | 4.20.3+127-gc42374a105-0+deb13u1 | [DEBIAN-CVE-2026-23558](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23558.md) | May 19, 2026 |
| Linux | xen Debian 14 | 4.20.3+127-gc42374a105-1 | [DEBIAN-CVE-2026-23558](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23558.md) | May 19, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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