Cyber Posture

CVE-2025-21418

HighCISA KEVActive Exploitation

Published: 11 February 2025

Published
11 February 2025
Modified
27 October 2025
KEV Added
11 February 2025
Patch
CVSS Score 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.1327 94.2th percentile
Risk Priority 44 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21418 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Windows 10 1607. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 5.8% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and AC-6 (Least Privilege).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Privilege Escalation (T1068). What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly remediates the elevation of privilege vulnerability in the Windows Ancillary Function Driver for WinSock by requiring timely application of Microsoft patches listed in the MSRC update guide.

prevent

Limits the scope and impact of exploitation by low-privileged local attackers through enforcement of least privilege on Windows systems.

detect

Identifies the presence of CVE-2025-21418 via vulnerability scanning, enabling proactive remediation before local exploitation.

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Local elevation of privilege vulnerability in Windows driver directly enables T1068 Exploitation for Privilege Escalation.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Deeper analysisAI

CVE-2025-21418 is an elevation of privilege vulnerability in the Windows Ancillary Function Driver for WinSock. Published on 2025-02-11, it carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and is linked to CWE-122, with additional NVD-CWE-noinfo classification. The flaw affects Windows systems utilizing this driver component.

A local attacker with low privileges can exploit the vulnerability through low-complexity means without requiring user interaction. Successful exploitation grants high-impact access to confidentiality, integrity, and availability, enabling privilege escalation on the targeted system.

Microsoft's update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21418 provides details on patching. The vulnerability appears in CISA's Known Exploited Vulnerabilities catalog at https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21418, signaling real-world exploitation.

Details

CWE(s)
KEV Date Added
11 February 2025

Affected Products

microsoft
windows 10 1607
≤ 10.0.10240.20915 · ≤ 10.0.10240.20915
microsoft
windows 10 1809
≤ 10.0.17763.6893 · ≤ 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 2008
all versions, r2
microsoft
windows server 2012
all versions, r2
microsoft
windows server 2016
≤ 10.0.14393.7785
+4 more product configuration(s) — see NVD for full list

CVEs Like This One

CVE-2025-21333Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-24985Same product: Microsoft Windows 10 1607both on KEV
CVE-2025-24993Same product: Microsoft Windows 10 1607both on KEV
CVE-2025-59230Same product: Microsoft Windows 10 1607both on KEV
CVE-2025-24990Same product: Microsoft Windows 10 1607both on KEV
CVE-2026-20840Same product: Microsoft Windows 10 1607
CVE-2026-20922Same product: Microsoft Windows 10 1607
CVE-2025-21378Same product: Microsoft Windows 10 1607
CVE-2026-20820Same product: Microsoft Windows 10 1607
CVE-2025-24995Same product: Microsoft Windows 10 1607

References