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XenOperating system

CVE-2017-10913

CRITICAL · 9.8 CVSS v3.0 Published 2017-07-05
Fix available
A fix is available. Upgrade to after 4.8.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable 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
The grant-table feature in Xen through 4.8.x provides false mapping information in certain cases of concurrent unmap calls, which allows backend attackers to obtain sensitive information or gain privileges, aka XSA-218 bug 1.

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

The grant-table feature in Xen hypervisor versions through 4.8.x contains a race condition in concurrent unmap operations that returns false mapping information to backend drivers. This allows malicious or compromised backend domains to read incorrect memory mappings, potentially exposing sensitive data from other VMs or the hypervisor itself, or escalate privileges.

MitigationUpgrade Xen to version 4.9 or later which contains the fix for XSA-218. If immediate patching is not possible, consider isolating untrusted backend domains and limiting their grant table permissions.

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:<= 4.8.1

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/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 installed Xen hypervisor version
    Run 'xl version' or 'xm version' to retrieve the running Xen hypervisor version number
    Affected if The version displayed is 4.8.1 or earlier (any version through 4.8.x)
  2. Confirm grant table feature is in use
    Examine domain configuration files for the presence of 'grant_table' or 'grant' related settings, or check running domains with 'xl list -l' for grant table allocations
    Affected if Any domain (especially backend domains) has grant table access enabled in its configuration
  3. Identify backend domains in the environment
    List all domains with 'xl list' and review their configurations, particularly looking for driver domains or paravirtualized domains that act as backends for other VMs
    Affected if There are domains configured as backend drivers (such as driver domains, stub domains, or network/backend PV drivers) that are not fully trusted
  4. Check for concurrent grant unmap operations
    Review system logs and monitoring data for evidence of simultaneous or high-frequency grant table unmap operations across multiple domains
    Affected if The environment handles workloads that trigger concurrent unmap operations in the grant table code path

You are affected if your Xen hypervisor version is 4.8.1 or earlier AND you have backend domains using grant table access, as this creates the conditions for the race condition to be exploitable.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 4.8.1
Interim mitigation

Upgrade Xen to version 4.9 or later which contains the fix for XSA-218. If immediate patching is not possible, consider isolating untrusted backend domains and limiting their grant table permissions.

Recommended fix Moderate confidence

Xen 4.9.0 or Xen 4.8.5 (or latest 4.8.x stable)

  1. 1. Identify the current Xen version running on the host using: `xl info` or `xm info`
  2. 2. Check if the version is <= 4.8.1
  3. 3. Plan for maintenance window as hypervisor upgrade requires host reboot
  4. 4. Upgrade Xen to version 4.9.0 or later, or to the latest 4.8.x stable patch level (e.g., 4.8.5)
  5. 5. For Debian systems: run `apt-get update && apt-get install xen-hypervisor` and reboot
  6. 6. For Gentoo systems: run `emerge --sync && emerge -av xen` and reboot
  7. 7. Verify the new Xen version is running post-reboot with `xl info | grep xen`
Caveat Hypervisor upgrade requires host reboot; ensure VMs are properly configured for live migration or plan downtime

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Xen Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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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-2017-10913 in production — separate from our analysis above.

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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