CVE-2013-6400
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 · uneditedXen 4.2.x and 4.3.x, when using Intel VT-d and a PCI device has been assigned, does not clear the flag that suppresses IOMMU TLB flushes when unspecified errors occur, which causes the TLB entries to not be flushed and allows local guest administrators to cause a denial of service (host crash) or gain privileges via unspecified vectors.
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 confidenceXen 4.2.x and 4.3.x with Intel VT-d and assigned PCI devices fails to clear a flag that suppresses IOMMU TLB flushes when unspecified errors occur, leaving stale TLB entries. This allows local guest administrators to cause host DoS (crash) or potentially gain privileges.
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= 4.2.0= 4.2.1= 4.2.2= 4.2.3= 4.3.0= 4.3.1CVSS 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
- High
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:A/AC:H/Au:N/C:C/I:C/A:C
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 checksWork through these to decide whether this CVE applies to you.
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Identify the installed Xen hypervisor versionRun `xl info` or `xm info` and look for the 'xen_version' field, or check the boot logs for the Xen version stringAffected if The version is 4.2.0, 4.2.1, 4.2.2, 4.2.3, 4.3.0, or 4.3.1
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Verify Intel VT-d is enabled in the hypervisorRun `xl dmesg | grep -i 'vt d'` or check the Xen boot parameters for 'intel_iommu=on' or 'iommu=force'Affected if Intel VT-d ( IOMMU) is enabled in the Xen configuration or boot parameters
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Determine if any PCI devices are assigned to guest domainsRun `xl pci-list-assigned` or check individual VM configurations with `xl pci-list <domain>` for any assigned PCI devicesAffected if Any PCI devices are currently assigned (passthrough) to guest virtual machines
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Check for recent IOMMU-related errors in Xen logsRun `xl dmesg` and search for IOMMU or TLB-related error messages, particularly those related to PCI device assignmentAffected if IOMMU TLB flush errors or related warning messages are present in the hypervisor logs
A system is affected if it runs Xen version 4.2.0-4.2.3 or 4.3.0-4.3.1 with Intel VT-d enabled and has PCI devices assigned to guest domains, as the bug only triggers under these specific conditions.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade to patched Xen version or disable VT-d/PCI device assignment if upgrade not feasible; this is a code-level bug requiring hypervisor update.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-6400 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2013-6400 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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