CVE-2026-23557

Xenstored DoS via XS_RESET_WATCHES command

MEDIUM
6.5
CVSS Score
Published: May 19, 2026 at 12:49 PM UTC
Updated: October 14, 2026 at 08:10 PM UTC
1 product affected across 1 vendorXen

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

Any guest can cause xenstored to crash by issuing a XS_RESET_WATCHES command within a transaction due to an assert() triggering. In case xenstored was built with NDEBUG #defined nothing bad will happen, as assert() is doing nothing in this case. Note that the default is not to define NDEBUG for xenstored builds even in release builds of Xen.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Xen· Xenwordpress-plugin
95%
v ≥ 4.2.0
Vendor states this is fixed in consult Xen advisory XSA-484 (unknown)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

PatchVendor Advisory
Source: cverecord
https://xenbits.xenproject.org/xsa/advisory-484.html
Mailing ListPatchThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/04/28/11
PatchVendor Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://xenbits.xen.org/xsa/advisory-484.html

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMCISA-ADP
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-617

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