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XenOperating system

CVE-2013-4356

MEDIUM · 5.4 CVSS v2.0 Published 2013-10-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
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
Xen 4.3.x writes hypervisor mappings to certain shadow pagetables when live migration is performed on hosts with more than 5TB of RAM, which allows local 64-bit PV guests to read or write to invalid memory and cause a denial of service (crash).

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

Xen 4.3.x contains a flaw in shadow pagetable handling where hypervisor memory mappings are incorrectly written during live migration on hosts exceeding 5TB of RAM. This causes 64-bit paravirtual guests to access invalid memory regions, leading to potential data corruption or hypervisor crashes.

MitigationUpgrade Xen to a version beyond 4.3.x (patches were included in subsequent releases). Avoid live migration on hosts with >5TB RAM until the hypervisor is patched.

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:= 4.3.0

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
Adjacent
Complexity
M
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:A/AC:M/Au:N/C:P/I:P/A:P

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 version
    Run 'xm version' or 'xl version' to determine the installed Xen hypervisor version
    Affected if Version equals 4.3.0 specifically
  2. Check total host RAM
    Run 'xm info' or 'xl info' and look at the 'total_memory' field, or use 'free -b' at host level and convert to terabytes
    Affected if Host has more than 5TB of physical RAM (greater than 5120GB)
  3. Identify guest type
    List all VMs with 'xm list' or 'xl list' and check if any are 64-bit paravirtual (PV) guests by examining the guest OS type or config
    Affected if 64-bit paravirtual guests are present on the host
  4. Monitor for migration activity
    During live migration events, check hypervisor logs (typically /var/log/xen/ or via 'xl dmesg') for errors related to shadow pagetables or memory mapping failures
    Affected if Live migration is performed on affected hosts with the conditions above

A host is affected only if running Xen 4.3.0 with more than 5TB RAM while hosting 64-bit paravirtual guests that undergo live migration, as the flaw specifically occurs in shadow pagetable handling during that operation.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Xen to a version beyond 4.3.x (patches were included in subsequent releases). Avoid live migration on hosts with >5TB RAM until the hypervisor is patched.

Fix this in Xen Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2013-4356 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