CVE-2017-10916
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 · uneditedThe vCPU context-switch implementation in Xen through 4.8.x improperly interacts with the Memory Protection Extensions (MPX) and Protection Key (PKU) features, which makes it easier for guest OS users to defeat ASLR and other protection mechanisms, aka XSA-220.
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 confidenceThe vCPU context-switch code in Xen through 4.8.x fails to properly handle MPX (Memory Protection Extensions) and PKU (Protection Keys) CPU features during virtual CPU state switching. This improper interaction allows guest OS users to potentially leak or infer memory addresses, facilitating attacks against ASLR and similar memory protection mechanisms within guest virtual machines.
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= 4.5.0= 4.5.1= 4.5.2= 4.5.3= 4.5.5= 4.6.0= 4.6.1= 4.6.2= 4.6.4= 4.6.5= 4.7.1= 4.8.0CVSS 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
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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.
-
Identify Xen hypervisor versionRun `xl version` or `xm version` to display the installed Xen hypervisor version numberAffected if Version is 4.5.0, 4.5.1, 4.5.2, 4.5.3, 4.5.5, 4.6.0, 4.6.1, 4.6.2, 4.6.4, 4.6.5, 4.7.1, or 4.8.0 from the affected product list
-
Verify host CPU supports MPX or PKU featuresRun `xl info` and examine the 'cpu_features' or 'flags' field for 'mpx' or 'pkru' (PKU) indicators, alternatively check `cat /proc/cpuinfo` for these CPU flagsAffected if Host CPUs expose MPX or PKU capability in hardware feature flags and the hypervisor version falls within the affected range
-
Determine if guests utilize MPX or PKU protectionsInspect guest VM configurations and running state. Check if any HVM or PV guests are actively using MPX (Memory Protection Extensions) or PKU (Protection Keys) CPU features, as the vulnerability is only exploitable when these guest features are in useAffected if Guest virtual machines are configured to use MPX or PKU features on a vulnerable Xen version
-
Confirm XSA-220 patch has not been appliedCheck Xen release notes or patch inventory for presence of the XSA-220 security fix, or compare hypervisor build date against the patch release dateAffected if The hypervisor lacks the XSA-220 fix and all other conditions (vulnerable version + MPX/PKU capable hardware + guest usage) are present
Environment is affected if running a Xen version from 4.5.0 through 4.8.0 on hardware supporting MPX/PKU, where guest VMs actively use these CPU features, and the XSA-220 security patch has not been applied.
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 Xen security patch for XSA-220 to all Xen hypervisors running vulnerable versions (4.8.x and earlier). Coordinate maintenance windows to update and reboot guest VMs after hypervisor patching to ensure the corrected context-switch behavior takes effect.
- Consultation6.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,448.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-10916 — 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-2017-10916 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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