Microsoft · Windows

CVE-2021-36942

Microsoft Windows Local Security Authority (LSA) Spoofing Vulnerability

Evidence

Source & freshness

Full source status →

CISA KEV catalog Core KEV record

CVE, vendor/product, CISA dates, ransomware status, description, required action, and notes.

Catalog 2026.07.24 · Retrieved 2026-07-25 20:49 UTC Open official CISA feed ↗

MITRE CWE catalog CWE context

CWE names and plain-language weakness descriptions. CISA supplies the CWE assignment itself.

Retrieved 2026-07-25 20:59 UTC Open official MITRE CWE catalog ↗

National Vulnerability Database NVD technical context

CVSS metrics, NVD timeline, and related NVD record data are stored locally.

Retrieved Jul 25, 2026, 08:49 PM UTC Open NVD record ↗

CISA KEV record

CISA date added: 2021-11-03
CISA due date: 2021-11-17
Known ransomware use: Known

NVD risk context

7.5 HIGH

CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.

View NVD record ↗

Attack vector

Network

The vulnerable service can be reached remotely over a network.

Attack complexity

Low

Exploitation does not require unusual conditions beyond normal attacker control.

Privileges required

None

The attacker does not need an existing account or privileges.

User interaction

None

No action by another user is required.

Description

Microsoft Windows Local Security Authority (LSA) contains a spoofing vulnerability allowing an unauthenticated attacker to call a method on the LSARPC interface and coerce the domain controller to authenticate against another server using NTLM.

Required action

Apply updates per vendor instructions.

NVD reference index

Vendor and remediation references

NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36942 ↗
PatchVendor Advisory NVD reference source: secure@microsoft.com

Other NVD references (2)

https://www.kb.cert.org/vuls/id/405600 ↗
ExploitThird Party AdvisoryUS Government Resource NVD reference source: secure@microsoft.com
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36942 ↗
US Government Resource NVD reference source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

MITRE CWE context

CWE classification

CWE-749 Exposed Dangerous Method or Function

The product provides an Applications Programming Interface (API) or similar interface for interaction with external actors, but the interface includes a dangerous method or function that is not properly restricted.

View official MITRE CWE details ↗

NVD record timing

NVD record timeline

These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.

NVD published: Aug 12, 2021, 06:15 PM UTC
NVD last updated: Jun 17, 2026, 03:59 AM UTC

Advanced: view the technical CVSS vector

This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

View NVD record ↗

CISA notes

https://nvd.nist.gov/vuln/detail/CVE-2021-36942

https://nvd.nist.gov/vuln/detail/CVE-2021-36942