CVE-2021-36934: in the CISA KEV catalogue
Microsoft Windows SAM Local Privilege Escalation Vulnerability. CISA added CVE-2021-36934 to the Known Exploited Vulnerabilities catalogue on 2022-02-10 with a default due date of 2022-02-24. Known ransomware campaign use: Unknown. Forensic triage flag: No.
If a Volume Shadow Copy (VSS) shadow copy of the system drive is available, users can read the SAM file which would allow any user to escalate privileges to SYSTEM level. (CISA description)
- Vendor / product
- Microsoft Windows
- CWE
- CWE-1220
- CISA required action
- Apply updates per vendor instructions.
- EPSS
- 67%, percentile 99 (scored 2026-11-03)
EPSS puts about 67 in 100 odds (67%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 99% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2021-36934 in the CISA KEV catalogue?
Yes. CISA added CVE-2021-36934 (Microsoft Windows SAM Local Privilege Escalation Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2022-02-10. CISA's default due date for it is 2022-02-24.
Is CVE-2021-36934 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2021-36934. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2021-36934?
CISA's required action: Apply updates per vendor instructions.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2021-36934