CVE-2015-8550
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, when used on a system providing PV backends, allows local guest OS administrators to cause a denial of service (host OS crash) or gain privileges by writing to memory shared between the frontend and backend, aka a double fetch vulnerability.
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 hypervisor contains a double-fetch vulnerability in its paravirtualized (PV) backend implementation. When Xen provides PV backend services, a local guest OS administrator can manipulate memory shared between the frontend and backend to either crash the host OS or escalate privileges to the host level.
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 dataall versions= 12CVSS 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
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/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 checksWork through these to decide whether this CVE applies to you.
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Confirm Xen hypervisor is in useCheck for Xen by running 'xl list' or 'xm list' or looking for 'xen' in /proc/xen/ or checking dmesg for Xen boot messagesAffected if The system is running Xen as the hypervisor (not KVM, VMware, etc.)
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Identify if PV backends are enabledCheck if any paravirtualized frontends are connected by examining /sys/class/xen/ or running 'xl list -long' to see running domains and their backend configurationsAffected if PV (paravirtualized) frontends/backends are active (not HVM-only) - the vulnerability only affects PV backend implementations
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Determine Xen versionRun 'xm info' or 'xl info' or check 'rpm -q xen' or 'xl version' to obtain the installed Xen version numberAffected if The Xen version is any version (the advisory states all versions are affected)
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Check for SUSE Linux Enterprise Real Time Extension 12If on SUSE, verify the specific product version with 'cat /etc/os-release' or 'hostnamectl' to confirm if running SUSE Linux Enterprise Real Time Extension version 12Affected if Running SUSE Linux Enterprise Real Time Extension version 12 specifically
A user is affected if they are running Xen as the hypervisor with paravirtualized (PV) backends enabled, regardless of Xen version, or if they are running SUSE Linux Enterprise Real Time Extension 12 with Xen PV backends.
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 dataApply the relevant Xen security patch (XSA-155). If immediate patching is not feasible, consider disabling unnecessary PV backends or migrating affected workloads to HVM-based virtualization where operationally feasible.
- Consultation4.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,736.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-8550 — 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-2015-8550 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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- Version or environment caveats, and links to real fixes
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