PatchSiren cyber security CVE debrief
CVE-2021-36942 Microsoft CVE debrief
CVE-2021-36942 is a Microsoft Windows Local Security Authority (LSA) spoofing vulnerability that CISA added to its Known Exploited Vulnerabilities catalog on 2021-11-03. CISA also marks it as associated with known ransomware campaign use, so this should be treated as a high-priority patching item for Windows environments.
- Vendor
- Microsoft
- Product
- Windows
- CVSS
- Unknown
- CISA KEV
- Listed
- Original CVE published
- 2021-11-03
- Original CVE updated
- 2021-11-03
- Advisory published
- 2021-11-03
- Advisory updated
- 2021-11-03
Who should care
Windows administrators, endpoint and server security teams, vulnerability management programs, and incident responders should prioritize this CVE, especially where Windows systems are broadly deployed or exposed to higher-risk user activity.
Technical summary
The publicly available record identifies this issue as a Microsoft Windows Local Security Authority (LSA) spoofing vulnerability. The supplied corpus does not include deeper technical details or a CVSS score, but it does confirm the vulnerability was listed in CISA's KEV catalog and associated with known exploitation activity.
Defensive priority
Urgent
Recommended defensive actions
- Apply Microsoft updates per vendor instructions as soon as possible.
- Prioritize remediation on internet-facing, high-value, and heavily used Windows systems.
- Confirm asset inventory coverage so all affected Windows endpoints and servers are included in patching.
- Validate that remediation completed successfully across the fleet.
- Monitor for suspicious authentication-related activity and investigate any signs of compromise in Windows environments.
Evidence notes
The source corpus confirms: Microsoft as vendor, Windows as the product, and the vulnerability name 'Microsoft Windows Local Security Authority (LSA) Spoofing Vulnerability.' CISA KEV lists the item with dateAdded 2021-11-03, dueDate 2021-11-17, requiredAction 'Apply updates per vendor instructions,' and knownRansomwareCampaignUse 'Known.' No CVSS score was provided in the supplied data.
Official resources
-
CVE-2021-36942 CVE record
CVE.org
-
CVE-2021-36942 NVD detail
NVD
-
CISA Known Exploited Vulnerabilities catalog
CISA - Apply updates per vendor instructions.
-
Source item URL
cisa_kev
CVE published and modified on 2021-11-03. CISA added the issue to the KEV catalog on the same date, with remediation due by 2021-11-17.