Vulnerability · Published May 19, 2026 · Assigned by XEN
CVE-2026-23558grant table v2 race in status page mapping
High 7.8
In plain English
A high-severity race condition in Xen from Xen. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | xen | 4.18.5-r7 | ALPINE-CVE-2026-23558 |
| Alpine:v3.21 | xen | 4.19.5-r2 | ALPINE-CVE-2026-23558 |
| Alpine:v3.22 | xen | 4.20.3-r2 | ALPINE-CVE-2026-23558 |
| Alpine:v3.23 | xen | 4.20.3-r2 | ALPINE-CVE-2026-23558 |
| Alpine:v3.24 | xen | 4.21.1-r3 | ALPINE-CVE-2026-23558 |
| Debian:12 | xen | 4.17.7-0+deb12u1 | DEBIAN-CVE-2026-23558 |
| Debian:13 | xen | 4.20.3+127-gc42374a105-0+deb13u1 | DEBIAN-CVE-2026-23558 |
| Debian:14 | xen | 4.20.3+127-gc42374a105-1 | DEBIAN-CVE-2026-23558 |
| Ubuntu:22.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-23558 |
| Ubuntu:24.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-23558 |
| Ubuntu:25.10 | xen | no fix listed | UBUNTU-CVE-2026-23558 |
| Ubuntu:26.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-23558 |
| Ubuntu:26.10 | xen | no fix listed | UBUNTU-CVE-2026-23558 |
Affected products (as reported)
Weakness: CWE-362 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H