CVE-2026-23555 | Xenstored DoS by unprivileged domain

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.

Published: 2026-03-23 Last update: 2026-04-10 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-23555 is rated Low Risk (29.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.02%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-23555

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-23 — 0.02% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23555

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.5 4.0 [email protected]
7.1 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.5 4.0 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-23555

OS Trackers for CVE-2026-23555

vendor priority summary link
alpine — CVE-2026-23555: 1 source package rows (xen); 101 state rows across 6 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 15, open 86. https://security.alpinelinux.org/vuln/CVE-2026-23555
debian end-of-life CVE-2026-23555 end-of-life priority: Debian including 1 source packages (xen), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 4, resolved 1. https://security-tracker.debian.org/tracker/CVE-2026-23555
suse high CVE-2026-23555 severity important: SUSE including 29 source package names (xen, xen-4.18.5_12-150600.3.40.1, …), 124 product×package rows across 32 product lines (Image SLES15-SP6-SAP-Azure-LI-BYOS, Image SLES15-SP6-SAP-Azure-LI-BYOS-Production, … (32 product lines)): Known Not Affected 83, Fixed 41. https://www.suse.com/security/cve/CVE-2026-23555/
ubuntu medium CVE-2026-23555 medium priority: Ubuntu including 1 source packages (xen), 7 status rows across 7 suites (bionic, focal, jammy, noble, questing, upstream, xenial): needs-triage 7. https://ubuntu.com/security/CVE-2026-23555

Affected software / configurations for CVE-2026-23555

Vendor Product Version Raw CPE
xen xen >= 4.18.0 cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:*

References for CVE-2026-23555

cvelogic Threat Intelligence