Medium 6.5Published May 19, 2026

CVE-2026-23557Xenstored DoS via XS_RESET_WATCHES command

Updated under an hour ago (Oct 27, 2026, 8:30 AM ET)

Does this affect you?

It affects Xen. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for Xen

Exploited in the last 30 days

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.

CVSS: 6.5 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Weakness (CWE): CWE-617
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: XEN
NVD analysis: Analyzed
Record last updated: May 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Xen Xen xen:xen (from the name)	consult Xen advisory XSA-484 status unknown	CNA record
xen xen xen:xen	from 4.2.0	NVD

References

References

https://xenbits.xenproject.org/xsa/advisory-484.html	patch, vendor-advisory
http://www.openwall.com/lists/oss-security/2026/04/28/11	mailing-list, patch, third-party-advisory
http://xenbits.xen.org/xsa/advisory-484.html	patch, vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.