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Debian LinuxOperating system · Debian

CVE-2022-42334

MEDIUM · 6.5 CVSS v3.1 Published 2023-03-21
Fix available
A fix is available. Upgrade to after 4.17.0 or later.
See remediation →
67/100
Remediation priority · Elevated
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
x86/HVM pinned cache attributes mis-handling T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] To allow cachability control for HVM guests with passed through devices, an interface exists to explicitly override defaults which would otherwise be put in place. While not exposed to the affected guests themselves, the interface specifically exists for domains controlling such guests. This interface may therefore be used by not fully privileged entities, e.g. qemu running deprivileged in Dom0 or qemu running in a so called stub-domain. With this exposure it is an issue that - the number of the such controlled regions was unbounded (CVE-2022-42333), - installation and removal of such regions was not properly serialized (CVE-2022-42334).

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 · high confidence

This CVE (CVE-2022-42334) addresses a race condition in Xen hypervisor where the installation and removal of HVM pinned cache attribute regions was not properly serialized. An unprivileged entity (such as qemu running deprivileged in Dom0 or a stub-domain) controlling HVM guests with passed-through devices could trigger this race condition via the cachability control interface, potentially leading to inconsistent cache state or other concurrency issues.

MitigationApply Xen security patches for CVE-2022-42334 which add proper serialization (locking) to cache region management operations. This is a hypervisor-level fix requiring update to a patched Xen version.

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
Debian LinuxOperating system
Affected:= 11.0
FedoraOperating system
Affected:= 37= 38
XenOperating system
Affected:>= 4.11.0, <= 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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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. Identify Xen hypervisor version
    Run 'xl info' or 'xm info' and locate the 'xen_version' field, or use 'dmesg | grep -i xen' and look for version information at boot
    Affected if The reported Xen version is between 4.11.0 and 4.17.0 inclusive (e.g., 4.11.x, 4.12.x, 4.13.x, 4.14.x, 4.15.x, 4.16.x, or 4.17.x)
  2. Confirm system runs as Xen host
    Run 'xl list' or 'xm list' to list running domains, or check for Xen-related processes with 'ps aux | grep -i xen'
    Affected if The system is running as a Xen hypervisor host (Dom0 is active)
  3. Identify HVM guests with PCI passthrough
    Run 'xl pci-list <domain_id>' for each domain, or examine domain configuration files in /etc/xen/ for 'pci' lines indicating passed-through devices
    Affected if There exist HVM (Hardware Virtual Machine) guests configured with PCI device passthrough (assigned PCI devices)
  4. Check for deprivileged qemu processes
    Run 'ps aux | grep -E "(qemu|pv-python)" | grep -v grep' to list qemu-related processes, or check stub-domain status with 'xl list -v' for domain types
    Affected if Qemu is running deprivileged (either in Dom0 as a deprivileged process or in a stub-domain) to manage HVM guests with passed-through devices

The environment is affected if running a Xen hypervisor version between 4.11.0 and 4.17.0 that hosts HVM guests with PCI passthrough, where qemu manages these guests from a deprivileged context in Dom0 or in stub-domains.

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.

From vendor data
Upgrade available Upgrade to a release after 4.17.0
Interim mitigation

Apply Xen security patches for CVE-2022-42334 which add proper serialization (locking) to cache region management operations. This is a hypervisor-level fix requiring update to a patched Xen version.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing16.0 h
  • Review / QA8.0 h
48.0 hours of engineering $8,320
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Scan for this in your stack

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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-2022-42334 in production — separate from our analysis above.

No notes yet

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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