Threats / Microsoft / CVE-2023-29336
CVE-2023-29336
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Microsoft Win32k vulnerability
Microsoft Win32k use-after-free vulnerability enables privilege escalation to SYSTEM. Actively exploited in the wild with high EPSS score.
Verdict
Today item — known-exploited.
A use-after-free flaw in Win32k allows attackers to escalate privileges to SYSTEM level. Active exploitation in the wild and high exploit probability indicate immediate risk to Windows systems.
CISA KEV Yes · 2023-05-095EPSS 0.40919 (verify live)6Exploit Public PoC7CVSS 7.83CISA SSVC Exploitation: active · Automatable: no · Impact: total4
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
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 2023-05-09).
Probability (EPSS)
EPSS 0.40919 — 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:U/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.
Weakness (CWE)
Mapped to CWE-416 Use After Free — weakness family: Memory safety.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
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 the same day 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 craft a malicious input that triggers a use-after-free condition in Win32k memory management.
Business
An attacker gains code execution in kernel context, bypassing all user-mode security boundaries.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I leverage the freed memory access to execute arbitrary code with SYSTEM privileges.
Business
Complete system compromise occurs, enabling installation of persistent malware, data exfiltration, and lateral movement.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistence mechanisms and maintain administrative control over the compromised host.
Business
Attackers retain long-term access to critical infrastructure, enabling ongoing espionage or sabotage operations.
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