Threats / Microsoft / CVE-2021-33739
CVE-2021-33739
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Microsoft Windows vulnerability
Microsoft Desktop Window Manager Core Library privilege escalation vulnerability allowing local attackers to gain elevated system privileges.
Verdict
Today item — known-exploited.
A privilege escalation flaw in Windows DWM enables local attackers to escalate from standard user to system-level access. Active exploitation in the wild indicates immediate risk to Windows deployments lacking mitigation.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
2 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 0.06555 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Windows. Confirm exact fixed builds in the vendor advisory.
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 standard user privileges on a target Windows system.
Business
Attacker gains foothold on endpoint through phishing, supply chain, or network compromise.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
Trigger the DWM Core Library vulnerability to escalate privileges to SYSTEM level.
Business
Attacker obtains full control of the compromised machine, bypassing user-level access controls.
3
Lateral reach — past segmentation narrative 3
Attacker
Install persistent malware, steal credentials, or pivot to other systems on the network.
Business
Attacker establishes durable presence for lateral movement, data exfiltration, or further compromise of enterprise infrastructure.
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