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Vulnerabilities

Vulnerability · CVE-2021-36942

Microsoft Windows Local Security Authority (LSA) Spoofing Vulnerability

Published Aug 12, 2021 · catalog updated Aug 10, 2026 · Microsoft Windows

Patch now

CVE-2021-36942 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Microsoft Windows against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
High7.5
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
66.02%
Remediation
Remediation guidance
Affected products
cpe microsoft/windows server 2004 · cpe microsoft/windows server 2008 · cpe microsoft/windows server 2012 · cpe microsoft/windows server 2016 · cpe microsoft/windows server 2019 · cpe microsoft/windows server 20h2

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. Initial-access exploit intelligence.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe microsoft/windows server 2004version unspecified
  • cpe microsoft/windows server 2008r2
  • cpe microsoft/windows server 2012r2
  • cpe microsoft/windows server 2016version unspecified
  • cpe microsoft/windows server 2019version unspecified
  • cpe microsoft/windows server 20h2version unspecified
  • vendor Microsoft Windowsversion unspecified

How to fix CVE-2021-36942

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-36942 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Microsoft Windows against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with microsoft/windows server 2008 r2; microsoft/windows server 2012 r2. Apply updates per vendor instructions.

What should an analyst verify?

CWE-749. EPSS 66.02%. The CISA KEV listing is the exploitation evidence. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.

Technology hubs

Windows security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 12, 2021 · Catalog

    Detected

    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.

  2. Nov 3, 2021 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Nov 17, 2021 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Aug 10, 2026 · Catalog

    Updated

    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.

Sources

  • CISA KEVConfirmed exploitationCVE-2021-36942

    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.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-36942

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-36942

    30-day exploitation probability 66.0%

    first.org
  • Metasploit ModulesPublic exploit moduleauxiliary_scanner/dcerpc/petitpotam

    Public module reference (normal). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDVulnerability recordCVE-2021-36942

    Windows LSA Spoofing Vulnerability

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2021-36942

    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.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.