Windows Server vulnerabilities: known CVEs & security history
Microsoft · Microsoft · 7 tracked CVEs · 0 actively exploited · updated September 2026 · what is a CVE? →
This is the full list of known vulnerabilities (CVEs) across all Windows Server release lines — 7 in total. A CVE here doesn't mean your version is affected — check Windows Server's current status and the safe version to run.
Known Windows Server CVEs
Actively-exploited and most-severe first. Open any CVE for full details.
| CVE | Severity | CVSS | EPSS | Year |
|---|---|---|---|---|
| CVE-2021-42283 | high | 8.8 | 0% | 2021 |
| CVE-2021-42286 | high | 7.8 | 0% | 2021 |
| CVE-2021-42285 | high | 7.8 | 0% | 2021 |
| CVE-2020-1082 | high | 7.8 | 1% | 2020 |
| CVE-2021-42291 | high | 7.5 | 3% | 2021 |
| CVE-2021-42282 | high | 7.5 | 3% | 2021 |
| CVE-2021-42284 | medium | 6.8 | 3% | 2021 |
Is my Windows Server version affected?
The list above spans every release. To know whether your version is affected — and the minimum safe version to upgrade to — check it directly.
Check your Windows Server version → · Monitor Windows Server for new CVEs →
Windows Server vulnerabilities — frequently asked
How many known vulnerabilities does Windows Server have?
IsItPatched tracks 7 CVEs for Windows Server. 0 are critical-severity and 6 high-severity. These span every release line — what matters is whether the version you run is affected.
Does Windows Server have any actively-exploited vulnerabilities?
None of Windows Server's tracked CVEs are currently in CISA's KEV catalog — but new ones can be added at any time, so keep your version current.
What is the most severe Windows Server vulnerability?
Among tracked issues, CVE-2021-42283 (HIGH, CVSS 8.8) ranks highest — a Improper privilege management weakness.
Is Windows Server safe to use?
It depends on the version. The latest supported Windows Server release (10.0.26100) clears the known issues; older versions may still be affected. Check the exact version you run for a verdict.
CVE data aggregated from NVD, CISA KEV and EPSS (FIRST.org). Related: Windows Server security status · Windows Server end-of-life · actively-exploited CVEs. Always verify against Microsoft's advisories — see our disclaimer.