CVE-2021-31199

What the flaw is

Microsoft Enhanced Cryptographic Provider contains an unspecified vulnerability that allows for privilege escalation.

Description as published by CISA. We have not independently reproduced it.

What CISA requires

Apply updates per vendor instructions.

This deadline is binding on US federal civilian agencies under BOD 22-01. It is not a legal deadline for anyone else, but it is a useful urgency signal — CISA sets it by how actively the flaw is being used, not by CVSS.

Public exploit code

2 public repositories referencing this CVE have been catalogued on GitHub. Treat this as a strong signal to prioritise patching, not as a verified working exploit — many such repositories are scanners, write-ups or forks rather than functional code.

• Ostorlab/KEV
• Ostorlab/known_exploited_vulnerbilities_detectors

Vendor advisories

• nvd.nist.gov/vuln/detail/CVE-2021-31199

Primary sources

• NVD entry — CVSS score, CPE list and references
• CISA KEV catalog — the source for this page
• CVE Record at cve.org