Vulnerability · Published Mar 23, 2026 · Assigned by XEN
CVE-2026-23555Xenstored DoS by unprivileged domain
High 7.1
In plain English
A high-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 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Any guest issuing a Xenstore command accessing a node using the (illegal) node path "/local/domain/", will crash xenstored due to a clobbered error indicator in xenstored when verifying the node path. Note that the crash is forced via a failing assert() statement in xenstored. In case xenstored is being built with NDEBUG #defined, an unprivileged guest trying to access the node path "/local/domain/" will result in it no longer being serviced by xenstored, other guests (including dom0) will still be serviced, but xenstored will use up all cpu time it can get.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | xen | 4.18.5-r5 | ALPINE-CVE-2026-23555 |
| Alpine:v3.21 | xen | 4.19.4-r2 | ALPINE-CVE-2026-23555 |
| Alpine:v3.22 | xen | 4.20.2-r2 | ALPINE-CVE-2026-23555 |
| Alpine:v3.23 | xen | 4.20.2-r2 | ALPINE-CVE-2026-23555 |
| Alpine:v3.24 | xen | 4.21.0-r3 | ALPINE-CVE-2026-23555 |
| Debian:13 | xen | 4.20.3+127-gc42374a105-0+deb13u1 | DEBIAN-CVE-2026-23555 |
| Debian:14 | xen | 4.20.3+127-gc42374a105-1 | DEBIAN-CVE-2026-23555 |
| Ubuntu:22.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-23555 |
| Ubuntu:24.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-23555 |
| Ubuntu:25.10 | xen | no fix listed | UBUNTU-CVE-2026-23555 |
| Ubuntu:26.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-23555 |
| Ubuntu:26.10 | xen | no fix listed | UBUNTU-CVE-2026-23555 |
Affected products (as reported)
Weakness: CWE-617 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H