Vulnerability · Published Jun 18, 2026 · Assigned by XEN
CVE-2026-42487x86 HVM I/O port list traversal
High 7.9
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 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
HVM guest I/O port accesses are subject to either emulation or at least translation. Translations are managed by the device model (via XEN_DOMCTL_ioport_mapping), and hence the linked list used may changed at any time. Traversal of those lists (while handling guest I/O port accesses) therefore needs synchronizing with updates, which was missing so far.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | xen | 4.18.5-r9 | ALPINE-CVE-2026-42487 |
| Alpine:v3.21 | xen | 4.19.5-r4 | ALPINE-CVE-2026-42487 |
| Alpine:v3.22 | xen | 4.20.3-r4 | ALPINE-CVE-2026-42487 |
| Alpine:v3.23 | xen | 4.20.3-r4 | ALPINE-CVE-2026-42487 |
| Alpine:v3.24 | xen | 4.21.1-r6 | ALPINE-CVE-2026-42487 |
| Debian:12 | xen | 4.17.7-0+deb12u1 | DEBIAN-CVE-2026-42487 |
| Debian:13 | xen | 4.20.3+127-gc42374a105-0+deb13u1 | DEBIAN-CVE-2026-42487 |
| Debian:14 | xen | 4.20.3+127-gc42374a105-1 | DEBIAN-CVE-2026-42487 |
| Ubuntu:22.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42487 |
| Ubuntu:24.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42487 |
| Ubuntu:25.10 | xen | no fix listed | UBUNTU-CVE-2026-42487 |
| Ubuntu:26.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42487 |
| Ubuntu:26.10 | xen | no fix listed | UBUNTU-CVE-2026-42487 |
Affected products (as reported)
Weakness: CWE-362 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H