CVE-2021-31201: Microsoft Enhanced Cryptographic Provider Privilege Escalation Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 3 Nov 2021, 148 days after the CVE record was published.

How likely is exploitation in the next 30 days?

2.6%

EPSS score, percentile 85.4 of all scored records

How severe?

5.2 Medium

CVSS v3.1 base score, given by the CNA

What should I do?

Required action (CISA), due 17 Nov 2021: Apply updates per vendor instructions.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected: 10.0.0 up to, not including, 10.0.17763.1999; 10.0.0 up to, not including, 10.0.17763.1999; 10.0.0 up to, not including, 10.0.17763.1999; 10.0.0 up to, not including, 10.0.18363.1621; 10.0.0 up to, not including, 10.0.19043.1052; 10.0.0 up to, not including, 10.0.19041.1052; 10.0.0 up to, not including, 10.0.19041.1052; 10.0.0 up to, not including, 10.0.19042.1052; 10.0.0 up to, not including, 10.0.19042.1052; 10.0.0 up to, not including, 10.0.10240.18967; 10.0.0 up to, not including, 10.0.14393.4467; 10.0.0 up to, not including, 10.0.14393.4467; 10.0.0 up to, not including, 10.0.14393.4467; 6.1.0 up to, not including, 6.1.7601.25632; 6.1.0 up to, not including, 6.1.7601.25632; 6.3.0 up to, not including, 6.3.9600.20045; 6.3.0 up to, not including, 6.3.9600.20044; 6.0.0 up to, not including, 6.0.6003.21137; 6.0.0 up to, not including, 6.0.6003.21137; 6.0.0 up to, not including, 6.0.6003.21137; 6.1.0 up to, not including, 6.1.7601.25632

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 17 November 2021.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

• https://nvd.nist.gov/vuln/detail/CVE-2021-31201

Affected products and versions

As listed in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

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

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2021-31201 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
• CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
• The due date CISA sets for the required action is 17 Nov 2021.
• The CVE record was published on 8 Jun 2021, 148 days before it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 5.2 (Medium), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 2.6% (percentile 85.4), as of 28 Oct 2026.
• CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact partial.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

Microsoft Enhanced Cryptographic Provider Elevation of Privilege Vulnerability

Microsoft Enhanced Cryptographic Provider Elevation of Privilege Vulnerability

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Timeline

References

• portal.msrc.microsoft.com

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