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XenOperating system

CVE-2022-42330

HIGH · 7.5 CVSS v3.1 Published 2023-01-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Guests can cause Xenstore crash via soft reset When a guest issues a "Soft Reset" (e.g. for performing a kexec) the libxl based Xen toolstack will normally perform a XS_RELEASE Xenstore operation. Due to a bug in xenstored this can result in a crash of xenstored. Any other use of XS_RELEASE will have the same impact.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

When a guest performs a soft reset (e.g., for kexec), the libxl Xen toolstack issues an XS_RELEASE operation to xenstored. Due to a bug in xenstored, this operation causes a crash of the xenstored daemon. Any XS_RELEASE Xenstore operation can trigger this crash, leading to denial of service for the Xen host environment.

MitigationApply Xen security patches for CVE-2022-42330 to update xenstored. If immediate patching is not possible, consider isolating critical workloads from untrusted guests and ensuring proper backup/recovery procedures for xenstored state.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
XenOperating system
Affected:= 4.17.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Xen hypervisor version
    Run `xl version` or `xm version` or check `/usr/lib/xen/bin/xenstored --version` if available, or look at package version with `rpm -q xen` or `dpkg -l xen`
    Affected if The installed Xen version is exactly 4.17.0
  2. Verify xenstored daemon is in use
    Check if xenstored process is running: `ps aux | grep xenstored` or check system service status like `systemctl status xenstored`
    Affected if xenstored is running as the Xen store daemon (this is the vulnerable component)
  3. Confirm Xen toolstack is libxl-based
    Check for libxl toolstack presence: look for `/usr/bin/libxl` or check if domain0 uses xl toolstack commands (`xl list` working), or examine `/etc/xen/xl.conf`
    Affected if The environment uses libxl (the default modern toolstack that issues the XS_RELEASE operation during guest reset)

You are affected if you are running Xen version 4.17.0 with the libxl toolstack and xenstored daemon, as any XS_RELEASE operation (triggered during guest soft reset/kexec or directly) will crash xenstored, causing host-wide denial of service.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Xen security patches for CVE-2022-42330 to update xenstored. If immediate patching is not possible, consider isolating critical workloads from untrusted guests and ensuring proper backup/recovery procedures for xenstored state.

Recommended fix Moderate confidence

Xen 4.17.1 or later point release

  1. Identify the current Xen version by running: xl version or cat /etc/xen/version
  2. Check for available Xen updates in your distribution's security repository or from xenproject.org
  3. Upgrade Xen to version 4.17.1 or later which contains the fix for the xenstored XS_RELEASE crash bug
  4. After upgrading, reboot the host to load the new xenstored and hypervisor
  5. Verify the xenstored service is running properly post-upgrade: ps aux | grep xenstored
  6. Test that guest operations (including soft reset) work correctly
Caveat Point releases within the same major version typically have minimal breaking changes; however, always review release notes for any guest compatibility or toolstack changes before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Xen Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-42330 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data