Threats / Microsoft / CVE-2019-0803
CVE-2019-0803
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Microsoft Win32k vulnerability
Microsoft Win32k privilege escalation vulnerability due to improper memory object handling, allowing kernel-mode code execution. Actively exploited in the wild.
Verdict
Today item — known-exploited.
A kernel privilege escalation flaw in Win32k with high exploitation likelihood. Attackers can escalate from user mode to kernel mode, enabling complete system compromise. Active exploitation in the wild elevates risk significantly.
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
11 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 0.4523 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Win32k. 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
I craft a malicious input or trigger a specific code path in Win32k to cause improper memory object handling.
Business
Endpoint security controls are bypassed as the attacker gains kernel-level privileges.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute arbitrary code with kernel-mode privileges to disable security features, install rootkits, or maintain persistence.
Business
System integrity is compromised; malware becomes difficult to detect and remove, leading to prolonged breach dwell time.
3
Lateral reach — past segmentation narrative 3
Attacker
I access sensitive data, modify system configurations, or pivot to other systems on the network.
Business
Confidentiality and integrity of critical systems are lost; regulatory compliance violations and reputational damage occur.
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