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Threats / Microsoft / CVE-2019-1458
CVE-2019-1458 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Microsoft Win32k vulnerability

A privilege escalation vulnerability in Windows Win32k component fails to properly handle objects in memory, allowing attackers to elevate privileges on affected systems.

Verdict

Today item, not a backlog item.

This vulnerability poses significant risk due to active exploitation in the wild and association with ransomware campaigns. The high EPSS score reflects widespread threat activity and ease of exploitation.

CISA KEV Yes · 2022-01-103Ransomware use Flagged3EPSS 0.74438 (verify live)4Exploit Public PoC5
01

Is it exploitable?

— the evidence, ranked above the score
Exploit 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
21 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 2022-01-10), flagged for known ransomware use.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.74438 — 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.
NVD ↗Reported
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution 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 board
1

Front door — unauthenticated access narrative 1

Attacker
I exploit the Win32k memory handling flaw to escalate from user-level to system privileges on a target Windows system.
Business
Attackers gain administrative control, enabling deployment of ransomware, data exfiltration, and lateral movement across enterprise infrastructure.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I use elevated privileges to install persistent malware and establish command-and-control communication channels.
Business
Ransomware operators encrypt critical business data and systems, demanding payment while disrupting operations and threatening data disclosure.
3

Lateral reach — past segmentation narrative 3

Attacker
I maintain access across multiple systems within the compromised network environment.
Business
Extended downtime, recovery costs, potential regulatory fines, reputational damage, and financial losses from ransom demands or data breach notifications.
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

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • Ransomware-use flag (CISA)
  • EPSS probability (FIRST)
  • Public PoC available (VulnCheck)
  • 21 reported-exploitation source(s)
  • Public exploit availability
  • Catalogued by microsoft (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by microsoftCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.