Skip to main content

Boteraser | Website and Server Security Solutions

🛡️ CVE-2026-23556 on Ubuntu — xen

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

When oxenstored is tearing a domain down, the node data is cleaned up but the usage counts are leaked. When the domain ID is eventually reused, the new domain can create fewer nodes before beeing deemed to be over quota.

Distribution advisory

This page covers CVE-2026-23556 as tracked by Ubuntu, for the package xen. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Attack requirements: None — no deployment-specific condition has to hold.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

UBUNTU-CVE-2026-23556 is classified as CWE-281: Improper Preservation of Permissions. Permissions are not carried over correctly during an operation such as copy or restore, widening access.

Affected software

UBUNTU-CVE-2026-23556 is recorded against 1 package.

  • xen

Timeline and source

Published on 9 July 2026 and last revised on 15 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
xenbits.xen.org (Report)

Other advisories for this package

xen has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-281: Improper Preservation of Permissions) in other software:

CVE-2026-23556 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-07-09
Updated 2026-08-20
Modified 2026-07-15
Fix URL N/A

Affected Packages

Software From version Fixed in
xen — —

Free Vulnerability Check

Is your site affected by UBUNTU-CVE-2026-23556?

BotEraser helps you identify potentially vulnerable plugins and themes by checking your installation against UBUNTU-CVE-2026-23556 and other known CVE records.

Scan My Site Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesUbuntuUbuntu 2026
✓