CVE-2021-42287
KEVRansomware UseMicrosoft Active Directory Domain Services Privilege Escalation Vulnerability
Description
Microsoft Active Directory Domain Services contains an unspecified vulnerability that allows for privilege escalation.
Active Directory Domain Services Elevation of Privilege Vulnerability
CVSS 3.1 vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HPublishedNov 10, 2021
Last modifiedAug 19, 2026
Added to KEVApr 11, 2022
Remediation dueMay 2, 2022
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42287PatchVendor Advisory
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42287PatchVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42287US Government Resource
0 recent articles mention this CVE
85
Risk assessment · Critical
Actively exploited and used by ransomware crews. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1639 days
- Ransomware
- Used in known ransomware campaigns
- CVSS
- 7.5 HIGH
- EPSS (30-day exploit probability)
- 77.2% · top 1% of all CVEs
- Weakness
- NVD-CWE-noinfo
- Attack vector
- Network, remotely reachable
Recommended actions
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
- 5.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.