Threats / Microsoft / CVE-2011-3402
CVE-2011-3402
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Microsoft Windows vulnerability
Microsoft Windows kernel TrueType font parsing vulnerability in win32k.sys allows remote code execution through malicious font data embedded in documents or web pages.
Verdict
Today item — known-exploited.
Remote attackers can achieve arbitrary code execution by crafting malicious TrueType font data delivered via Word documents or web content, exploiting a parsing flaw in the Windows kernel-mode font engine.
CISA KEV Yes · 2025-10-064EPSS 0.78285 (verify live)5CVSS 8.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3Exploit Public PoC / detection · Metasploit module12
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
10 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 2025-10-06).
Probability (EPSS)
EPSS 0.78285 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) · Affected: Microsoft, Windows. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
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 5085 days after 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.
Public exploit available
Public exploit tooling is catalogued for this CVE (a public proof-of-concept / detection template). Catalog entries: Metasploit module. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
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 TrueType font and embed it in a Word document or host it on a web page.
Business
An employee or user downloads and opens the document or visits the compromised web page.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I trigger the vulnerable font parsing code in win32k.sys when the system processes the malicious font data.
Business
The kernel-mode driver processes untrusted font input without proper validation.
3
Lateral reach — past segmentation narrative 3
Attacker
I execute arbitrary code with kernel privileges on the target system.
Business
The attacker gains complete system compromise, enabling data theft, malware installation, or lateral movement.
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