Threats / Microsoft / CVE-2021-41357
CVE-2021-41357
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Microsoft Win32k vulnerability
Microsoft Win32k privilege escalation vulnerability exploited in the wild. Allows attackers to elevate privileges on affected Windows systems.
Verdict
Today item — known-exploited.
Unspecified privilege escalation in Win32k with active exploitation observed. Low EPSS score suggests limited weaponization complexity, but real-world exploitation confirms practical threat. Patching recommended.
CISA KEV Yes · 2022-04-255EPSS 0.01968 (verify live)6CVSS 7.83CISA SSVC Exploitation: active · Automatable: no · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
1 independent public report 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 2022-04-25).
Probability (EPSS)
EPSS 0.01968 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C) · Affected: Microsoft, Win32k. 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 194 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
Execute code with limited privileges on a target Windows system.
Business
Attacker gains foothold on endpoint with user-level access.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
Trigger Win32k vulnerability to escalate privileges to system or administrator level.
Business
Attacker obtains elevated permissions, bypassing access controls.
3
Lateral reach — past segmentation narrative 3
Attacker
Maintain persistence and execute arbitrary operations with elevated rights.
Business
Attacker can install malware, modify system configuration, or access sensitive data across the organization.
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