Vulnerability Snapshot
CVE-2017-0021 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.
Affected technology: windows_10, windows_server_2016.
Executive Summary
Hyper-V in Microsoft Windows 10 1607 and Windows Server 2016 does not properly validate vSMB packet data, which allows attackers to execute arbitrary code on a target OS, aka "Hyper-V System Data Structure Vulnerability." This vulnerability is different from that described in CVE-2017-0095.
Why It Matters
CVE-2017-0021 is rated CRITICAL severity, requiring immediate attention from security teams.
CVSS Base Score: 9/10
Affected Technologies
Vendors: microsoft
Products: windows_10, windows_server_2016
🛡️What Defenders Should Check
Use Vulnios to continuously monitor your exposure to CVE-2017-0021 and similar vulnerabilities.
References & Sources
How Vulnios Detects This
Vulnios scans for this vulnerability using KEV cross-check that flags any host where this CVE is already on CISA's exploited list. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.
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Affected Products
Sources
Related Threat Alerts
- Critical Vulnerability: CVE-2017-0028 — microsoft — edge
- Critical Vulnerability: CVE-2017-8589 — microsoft — windows_10, windows_7
- Critical Vulnerability: CVE-2017-0252 — microsoft — edge
- Critical Vulnerability: CVE-2017-0223 — microsoft — edge
- Critical Vulnerability: CVE-2017-6517 — microsoft — skype
- High Vulnerability: CVE-2004-0210 — microsoft — interix, windows_2000
Frequently Asked Questions
What is CVE-2017-0021?
CVE-2017-0021 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. Hyper-V in Microsoft Windows 10 1607 and Windows Server 2016 does not properly validate vSMB packet data, which allows attackers to execute arbitrary code on a target OS, aka "Hyper-V System Data Stru
Am I affected?
Check whether your environment runs windows_10, windows_server_2016. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.
How urgent is the response?
Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.
How do I remediate?
Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.
Where can I track exploitation activity?
Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2017-0021. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.
How does Vulnios help with this?
Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.
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