6.5

CVE-2026-23557: Xenstored DoS via XS_RESET_WATCHES command

Analyzed
AliasesALPINE-CVE-2026-23557UBUNTU-CVE-2026-23557DEBIAN-CVE-2026-23557
Published 19-05-2026Last modified 19-05-2026

Vulnerability summary

CVE-2026-23557 is a medium (CVSS 6.5) Reachable Assertion vulnerability in xen. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 4.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.16%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2026:10660-1

Timeline

  1. 19-05-2026
    PublishedVulnerability first disclosed.
  2. 19-05-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

5%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.16% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Alpine1 product
  • xen≥ 4.2.0, < 4.18.5-r7 | ≥ 4.2.0, < 4.19.5-r2 | ≥ 4.2.0, < 4.20.3-r2 | ≥ 4.2.0, < 4.21.1-r3
Debian1 product
  • xen< 4.17.7-0+deb12u1 | < 4.20.3+127-gc42374a105-0+deb13u1 | < 4.20.3+127-gc42374a105-1
Ubuntu1 product
  • xenAll versions (No fix recorded)
Xen1 product
  • xen≥ 4.2.0 (No fix recorded)

4 vendors · 4 products

References

8 links