Threats / Microsoft / CVE-2021-31199
CVE-2021-31199
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Microsoft Enhanced Cryptographic Provider vulnerability
Microsoft Enhanced Cryptographic Provider contains an unspecified privilege escalation vulnerability that has been exploited in the wild.
Verdict
Today item — known-exploited.
A privilege escalation flaw in Microsoft's Enhanced Cryptographic Provider enables attackers to gain elevated system access. Active exploitation in the wild indicates immediate risk to affected systems.
CISA KEV Yes · 2021-11-035EPSS 0.02954 (verify live)6CVSS 5.23CISA SSVC Exploitation: active · Automatable: no · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
5 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03).
Probability (EPSS)
EPSS 0.02954 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 5.2 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C) · Affected: Microsoft, Enhanced Cryptographic Provider. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 148 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify and exploit a privilege escalation weakness in the Enhanced Cryptographic Provider to elevate my access level on the target system.
Business
An attacker gains administrative or system-level privileges, enabling full system compromise and lateral movement within the network.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I use elevated privileges to install persistent backdoors, modify system configurations, or exfiltrate sensitive data.
Business
The organization faces data breach, system integrity compromise, and potential regulatory violations from unauthorized access to protected information.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05