Vulnerability · Published Jun 18, 2026 · Assigned by XEN
CVE-2026-42490domctl lock open to abuse
Medium 6.5
In plain English
A medium-severity security flaw 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 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] To create and manage guests, domctl operations are used by the control domain, a possible Xenstore domain, or by a domain controlling a particular guest. Some of these operations may not be executed in parallel, so a system-wide lock is used. The way that lock is acquired is, however, not providing any fairness. This is CVE-2026-42489. Furthermore, with XSM/Flask in use, the lock acquire will, for some operations, occur ahead of any permission checking. This is CVE-2026-42490.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | xen | 4.18.5-r9 | ALPINE-CVE-2026-42490 |
| Alpine:v3.21 | xen | 4.19.5-r4 | ALPINE-CVE-2026-42490 |
| Alpine:v3.22 | xen | 4.20.3-r4 | ALPINE-CVE-2026-42490 |
| Alpine:v3.23 | xen | 4.20.3-r4 | ALPINE-CVE-2026-42490 |
| Alpine:v3.24 | xen | 4.21.1-r6 | ALPINE-CVE-2026-42490 |
| Debian:12 | xen | 4.17.7-0+deb12u1 | DEBIAN-CVE-2026-42490 |
| Debian:13 | xen | 4.20.3+127-gc42374a105-0+deb13u1 | DEBIAN-CVE-2026-42490 |
| Debian:14 | xen | 4.20.3+127-gc42374a105-1 | DEBIAN-CVE-2026-42490 |
| Ubuntu:22.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42490 |
| Ubuntu:24.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42490 |
| Ubuntu:25.10 | xen | no fix listed | UBUNTU-CVE-2026-42490 |
| Ubuntu:26.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42490 |
| Ubuntu:26.10 | xen | no fix listed | UBUNTU-CVE-2026-42490 |
Affected products (as reported)
Weakness: CWE-667 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H