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Threats / Microsoft / CVE-2016-7255
CVE-2016-7255 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Microsoft Win32k vulnerability

Microsoft Win32k kernel-mode driver improperly handles memory objects, enabling privilege escalation and kernel-mode code execution.

Verdict

Today item — known-exploited.

A memory handling flaw in Win32k allows local attackers to escalate privileges and execute arbitrary code with kernel privileges. The high EPSS score and active exploitation in the wild indicate significant real-world risk.

CISA KEV Yes · 2021-11-033EPSS 0.80968 (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
14 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).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.80968 — 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
Weakness (CWE)
Mapped to CWE-264 Permissions/Privileges/Access Control — weakness family: Authorization / access control.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
WeaknessCWE-264 · Permissions/Privileges/Access ControlAuthorization / access control
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 gain initial access to a target system as a standard user or through a compromised application.
Business
An attacker establishes a foothold on the network with limited privileges, creating an entry point for further compromise.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I craft a malicious input or trigger a specific sequence of operations that causes Win32k to mishandle a kernel object in memory.
Business
The vulnerability becomes the pivot point for converting user-level access into system-level control.
3

Lateral reach — past segmentation narrative 3

Attacker
I execute code that exploits the memory handling flaw to escalate my privileges to kernel mode.
Business
The attacker gains unrestricted control over the operating system, bypassing all security boundaries and access controls.
4

Data at risk — exfiltration narrative 4

Attacker
I run arbitrary code with kernel privileges, allowing me to install rootkits, disable security software, or move laterally across the network.
Business
Complete system compromise enables data theft, malware persistence, lateral movement, and potential compromise of connected 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

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • EPSS probability (FIRST)
  • Public PoC available (VulnCheck)
  • 14 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • 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.