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CVE

CVE-2025-21418

Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability.

HIGH · CVSS 7.8 ⚠ CISA KEV EPSS 0.1327
Act now
  • Listed on CISA KEV (known exploited in the wild)
  • SSVC exploitation status: active
  • EPSS ≥ 0.10 - elevated exploitation probability
  • EPSS percentile: top 6% of all CVEs by exploitation likelihood
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬢

Required Remediation

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

⬡

Weakness Classification

CWE-122Heap-based Buffer Overflow
▤

Affected Products & Versions

14
microsoft windows 10 1607< 10.0.10240.20915
microsoft windows 10 1809< 10.0.17763.6893
microsoft windows 10 21h2< 10.0.19044.5487
microsoft windows 10 22h2< 10.0.19045.5487
microsoft windows 11 22h2< 10.0.22621.4890
microsoft windows 11 23h2< 10.0.22631.4890
microsoft windows 11 24h2< 10.0.26100.3107
microsoft windows server 2008all versions
▣

Scoring & Timeline

7.8
HIGH · CVSS v3.1 · secure@microsoft.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD11 Feb 2025 · 06:15 PM
CVSS VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
active
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

2
msrcCVE-2025-21418Elevation of Privilege
cisaKEV-CVE-2025-21418
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21418US Government Resource
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