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XenOperating system

CVE-2015-8554

HIGH · 7.5 CVSS v3.0 Published 2016-04-14
Fix available
A fix is available. Upgrade to after 4.6.1 or later.
See remediation →
77/100
Remediation priority · High
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
Buffer overflow in hw/pt-msi.c in Xen 4.6.x and earlier, when using the qemu-xen-traditional (aka qemu-dm) device model, allows local x86 HVM guest administrators to gain privileges by leveraging a system with access to a passed-through MSI-X capable physical PCI device and MSI-X table entries, related to a "write path."

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

Buffer overflow in Xen's hw/pt-msi.c when using qemu-xen-traditional device model allows local x86 HVM guest administrators to gain host privileges by overflowing buffers in the MSI-X table entry write path for passed-through PCI devices.

MitigationUpgrade Xen beyond 4.6.x to obtain the fixed version, or disable PCI passthrough for untrusted guests if upgrading is not feasible.

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:<= 4.6.1

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
High
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/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 version
    Run 'xl info' or 'xm info' and look for the Xen version line
    Affected if Version is 4.6.1 or earlier (4.6.x series)
  2. Determine the device model in use
    Check HVM guest configuration file (typically in /etc/xen/<guest-name>.cfg) for the 'device_model' setting
    Affected if Device model is set to 'qemu-xen-traditional' (not 'qemu-xen' or upstream qemu)
  3. Verify PCI passthrough is enabled
    Check the guest config for 'pci' or 'pcifront' entries that assign host PCI devices to the guest, or run 'xl pci-list <guest-name>'
    Affected if Guest has assigned PCI devices via passthrough configuration
  4. Confirm HVM guest type
    Check guest configuration for 'builder = "hvm"' or verify with 'xl list -l <guest-name>'
    Affected if Guest is an HVM (Hardware Virtual Machine) domain

User is affected if running Xen 4.6.1 or earlier with qemu-xen-traditional as device model and with PCI passthrough enabled for an HVM guest

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 4.6.1
Interim mitigation

Upgrade Xen beyond 4.6.x to obtain the fixed version, or disable PCI passthrough for untrusted guests if upgrading is not feasible.

Fix this in Xen Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,392.

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-2015-8554 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