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XenOperating system

CVE-2025-58143

CRITICAL · 9.8 CVSS v3.1 Published 2025-09-11
Fix available
A fix is available. Upgrade to 4.17.0 or later.
See remediation →
100/100
Remediation priority · Urgent
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
[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] There are multiple issues related to the handling and accessing of guest memory pages in the viridian code: 1. A NULL pointer dereference in the updating of the reference TSC area. This is CVE-2025-27466. 2. A NULL pointer dereference by assuming the SIM page is mapped when a synthetic timer message has to be delivered. This is CVE-2025-58142. 3. A race in the mapping of the reference TSC page, where a guest can get Xen to free a page while still present in the guest physical to machine (p2m) page tables. This is CVE-2025-58143.

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

A race condition in Xen's viridian code allows a malicious guest to trigger Xen into freeing a reference TSC page while that page remains mapped in the guest's p2m (physical to machine) page tables, potentially causing use-after-free or memory corruption leading to hypervisor compromise.

MitigationApply the Xen hypervisor security patch for CVE-2025-58143 to fix the race condition in reference TSC page handling; affected systems should be updated 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
XenOperating system
Affected:>= 4.13.0, < 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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 version` or `xm version` to retrieve the running Xen hypervisor version number
    Affected if The version is greater than or equal to 4.13.0 AND less than 4.17.0
  2. Verify Viridian feature is enabled
    Examine domain configuration files in /etc/xen/ or check running domain configuration using `xl list -l <domain_name>` and look for the 'viridian' or 'reference_tsc' option set to 1
    Affected if Any domain has Viridian (hypervisor_cpuid) or reference TSC page feature enabled in its configuration
  3. Check for active guest domains
    Run `xl list` to list all running domains. An attacker needs a malicious guest to trigger the race condition, so running guest domains increase exposure
    Affected if There are active guest domains (domU) running on the Xen host, particularly Windows guests which commonly use Viridian features
  4. Confirm vulnerability context
    The race condition occurs in reference TSC page handling within the Viridation code. This feature is typically used for accurate timekeeping in Windows paravirtualized guests
    Affected if Windows-based VMs with Viridian/TSC page features are in use, as this is the specific code path containing the race condition

You are affected if your Xen hypervisor version is 4.13.0 through 4.16.x inclusive AND you run guest domains with Viridian or reference TSC page features enabled, as this triggers the vulnerable code path.

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
Upgrade available Upgrade to 4.17.0 or later
Fixed in 4.17.0
Interim mitigation

Apply the Xen hypervisor security patch for CVE-2025-58143 to fix the race condition in reference TSC page handling; affected systems should be updated to a patched Xen version.

Recommended fix High confidence

Xen 4.17.0 or later

  1. 1. Identify the current Xen version by running `xl info` or checking the Xen packages installed
  2. 2. Plan downtime for the hypervisor upgrade, as this requires host reboot
  3. 3. Back up all VM configurations (xe vm-list, xe vm-export, or libvirt XML backups as applicable)
  4. 4. Upgrade Xen to version 4.17.0 or later using your distribution's package manager (e.g., `apt-get update && apt-get install xen-hypervisor` or `yum update xen-x86_64`)
  5. 5. Verify the upgrade installed version 4.17.0 or newer
  6. 6. Reboot the host to load the new hypervisor
  7. 7. After reboot, confirm the running Xen version is >= 4.17.0 using `xl info`
  8. 8. Restart affected VMs to ensure they are running on the patched hypervisor
Caveat Upgrading Xen hypervisor requires host reboot and VM downtime; ensure compatibility of VM configurations with the new version before production deployment

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

Fix this in Xen Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA6.0 h
30.0 hours of engineering $5,120
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,192.

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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-2025-58143 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