CVE-2025-21418
published 2025-02-11CVE-2025-21418: Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
PriorityP180high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
KEVITW
CISA Known Exploited Vulnerabilitydue 2025-03-04
Exploited in the wild
EPSS
1.54%
72.2th percentile
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Affected
46 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| 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 | 10.0.19044.5487 |
| microsoft | windows_10_22h2 | < 10.0.19045.5487 | 10.0.19045.5487 |
| microsoft | windows_10_version_1507 | >= 10.0.10240.0 < 10.0.10240.20915 | 10.0.10240.20915 |
| microsoft | windows_10_version_1607 | >= 10.0.14393.0 < 10.0.14393.7785 | 10.0.14393.7785 |
| microsoft | windows_10_version_1809 | >= 10.0.17763.0 < 10.0.17763.6893 | 10.0.17763.6893 |
| microsoft | windows_10_version_21h2 | >= 10.0.19044.0 < 10.0.19044.5487 | 10.0.19044.5487 |
| microsoft | windows_10_version_22h2 | >= 10.0.19045.0 < 10.0.19045.5487 | 10.0.19045.5487 |
| microsoft | windows_11_22h2 | < 10.0.22621.4890 | 10.0.22621.4890 |
| microsoft | windows_11_23h2 | < 10.0.22631.4890 | 10.0.22631.4890 |
| microsoft | windows_11_24h2 | < 10.0.26100.3107 | 10.0.26100.3107 |
| microsoft | windows_11_version_22h2 | >= 10.0.22621.0 < 10.0.22621.4890 | 10.0.22621.4890 |
| microsoft | windows_11_version_22h3 | >= 10.0.22631.0 < 10.0.22631.4890 | 10.0.22631.4890 |
| microsoft | windows_11_version_23h2 | >= 10.0.22631.0 < 10.0.22631.4890 | 10.0.22631.4890 |
| microsoft | windows_11_version_24h2 | >= 10.0.26100.0 < 10.0.26100.3194 | 10.0.26100.3194 |
| microsoft | windows_server_2008 | — | — |
| microsoft | windows_server_2008_r2_service_pack_1 | >= 6.1.7601.0 < 6.1.7601.27566 | 6.1.7601.27566 |
| microsoft | windows_server_2008_service_pack_2 | >= 6.0.6003.0 < 6.0.6003.23117 | 6.0.6003.23117 |
| microsoft | windows_server_2012 | — | — |
| microsoft | windows_server_2012 | >= 6.2.9200.0 < 6.2.9200.25317 | 6.2.9200.25317 |
| microsoft | windows_server_2012_r2 | >= 6.3.9600.0 < 6.3.9600.22417 | 6.3.9600.22417 |
| microsoft | windows_server_2016 | < 10.0.14393.7785 | 10.0.14393.7785 |
| microsoft | windows_server_2016 | >= 10.0.14393.0 < 10.0.14393.7785 | 10.0.14393.7785 |
| microsoft | windows_server_2019 | < 10.0.17763.6893 | 10.0.17763.6893 |
Detection & IOCsextracted from sources · hover to see the quote
- →Target component for detection: Windows Ancillary Function Driver for WinSock (afd.sys) — monitor for heap-based buffer overflow exploitation leading to SYSTEM privilege escalation from a local user context ↗
- →Exploitation requires no user interaction and has low attack complexity — prioritize detection of unexpected SYSTEM-level process spawning from low-privileged user processes interacting with WinSock/AFD driver ↗
- →Correlate with prior Lazarus Group TTPs: CVE-2024-38193 (same AFD component) was used to deploy FudModule rootkit — hunt for rootkit indicators and persistence mechanisms on systems where AFD exploitation is suspected ↗
- →Monitor for exploitation of the AFD/WinSock driver resulting in SYSTEM privilege gain — successful exploitation grants full SYSTEM privileges ↗
- →CVE-2025-21418 is confirmed actively exploited in the wild (Exploitation Detected) — treat any anomalous AFD driver interactions as high-priority alerts ↗
- →Since 2022, nine EoP vulnerabilities have been found in this same Windows component (three per year) — ensure continuous monitoring of afd.sys / WinSock ancillary function driver for anomalous kernel interactions ↗
- ·Attribution to Lazarus Group is unconfirmed for CVE-2025-21418 — do not treat Lazarus/FudModule as a definitive indicator without further evidence ↗
- ·No technical exploitation details, PoC, or specific IOCs (hashes, IPs, domains, filenames) have been publicly disclosed for CVE-2025-21418 as of the available sources ↗
CVSS provenance
nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vulncheck7.8HIGH
cisa7.8HIGH
vendor_msrc7.8HIGH
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GHSA
GHSA-5fhq-7w32-vhww: Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
ghsa_unreviewed·2025-02-11
CVE-2025-21418 [HIGH] CWE-122 GHSA-5fhq-7w32-vhww: Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
VulnCheck
Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability
vulncheck·2025·CVSS 7.8
CVE-2025-21418 [HIGH] CWE-122 Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability
Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability
Microsoft Windows Ancillary Function Driver for WinSock contains a heap-based buffer overflow vulnerability that allows for privilege escalation, enabling a local attacker to gain SYSTEM privileges.
Affected: Microsoft Windows
Required Action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Exploitation References: https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2025-Feb; https://docs.google.com/spreadsheets/d/1lkNJ0uQwbeC1ZTRrxdtuPLCIl7mlUreoKfSIgajnSyY/edit; https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2025-21418; https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json; https://www.loginsof
Microsoft
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
vendor_msrc·2025-02-11·CVSS 7.8
CVE-2025-21418 [HIGH] CWE-122 Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
FAQ: What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.
Windows Ancillary Function Driver for WinSock: Windows Ancillary Function Driver for WinSock
Microsoft: Microsoft
Customer Action Required: Yes
Impact: Elevation of Privilege
Exploit Status: Publicly Disclosed:No;Exploited:Yes;Latest Software Release:Exploitation Detected
Reference: https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5052000
Reference: https://support.microsoft.com/help/5052000
Reference: https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5051979
Reference: https://support.micros
CISA
Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability
cisa·2025-02-11·CVSS 7.8
CVE-2025-21418 [HIGH] CWE-122 Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability
Vulnerability: Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability
Affected: Microsoft Windows
Microsoft Windows Ancillary Function Driver for WinSock contains a heap-based buffer overflow vulnerability that allows for privilege escalation, enabling a local attacker to gain SYSTEM privileges.
Required Action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Notes: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21418 ; https://nvd.nist.gov/vuln/detail/CVE-2025-21418
Remediation Due Date: 2025-03-04
No detection rules found.
No public exploits indexed.
Tenable
Microsoft’s May 2025 Patch Tuesday Addresses 71 CVEs (CVE-2025-32701, CVE-2025-32706, CVE-2025-30400)
blogs_tenable·2025-05-13·CVSS 7.8
[HIGH] Microsoft’s May 2025 Patch Tuesday Addresses 71 CVEs (CVE-2025-32701, CVE-2025-32706, CVE-2025-30400)
## Cloud Exposure
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## Vulnerability Exposure
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## AI Exposure
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## OT/IoT Exposure
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## Identity Exposure
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## Business needs
Active Directory
AI Security Posture Management (AI-SPM)
AWS security
Azure security
Cloud Security Posture Man
Krebs
Microsoft Patch Tuesday, February 2025 Edition
blogs_krebs·2025-02-12·CVSS 7.8
CVE-2025-21418 [HIGH] Microsoft Patch Tuesday, February 2025 Edition
Microsoft today issued security updates to fix at least 56 vulnerabilities in its Windows operating systems and supported software, including two zero-day flaws that are being actively exploited.
All supported Windows operating systems will receive an update this month for a buffer overflow vulnerability that carries the catchy name CVE-2025-21418 . This patch should be a priority for enterprises, as Microsoft says it is being exploited, has low attack complexity, and no requirements for user interaction.
Tenable senior staff research engineer Satnam Narang noted that since 2022, there have been nine elevation of privilege vulnerabilities in this same Windows component — three each year — including one in 2024 that was exploited in the wild as a zero day (CVE-2024-38193).
“CVE-2024-3819
Krebs
Microsoft Patch Tuesday, February 2025 Edition
blogs_krebs·2025-02-12·CVSS 7.8
CVE-2025-21418 [HIGH] Microsoft Patch Tuesday, February 2025 Edition
Microsoft today issued security updates to fix at least 56 vulnerabilities in its Windows operating systems and supported software, including two zero-day flaws that are being actively exploited.
All supported Windows operating systems will receive an update this month for a buffer overflow vulnerability that carries the catchy name CVE-2025-21418. This patch should be a priority for enterprises, as Microsoft says it is being exploited, has low attack complexity, and no requirements for user interaction.
Tenable senior staff research engineer Satnam Narang noted that since 2022, there have been nine elevation of privilege vulnerabilities in this same Windows component — three each year — including one in 2024 that was exploited in the wild as a zero day (CVE-2024-38193).
“CVE-2024-38193
Talos
Microsoft Patch Tuesday for February 2025 — Snort rules and prominent vulnerabilities
blogs_talos·2025-02-11·CVSS 8.7
CVE-2025-21376 [HIGH] Microsoft Patch Tuesday for February 2025 — Snort rules and prominent vulnerabilities
Microsoft has released its monthly security update for February of 2025 which includes 63 vulnerabilities affecting a range of products, including 4 that Microsoft marked as “critical” and one marked as "moderate."
There are two notable "critical" vulnerabilities. The first is CVE-2025-21376, which is a remote code execution (RCE) vulnerability affecting the Windows Lightweight Directory Access Protocol (LDAP). This vulnerability is a remote unauthenticated Out-of-bounds Write (OOBW) caused by a race condition in LDAP and could potentially result in arbitrary code execution in the Local Security Authority Subsystem Service (lsass.exe). This is a process in the Microsoft Windows operating systems that is responsible for enforcing the security policy on the system. Successful exploitation o
Talos
Microsoft Patch Tuesday for February 2025 — Snort rules and prominent vulnerabilities
blogs_talos·2025-02-11·CVSS 8.7
CVE-2025-21376 [HIGH] Microsoft Patch Tuesday for February 2025 — Snort rules and prominent vulnerabilities
## Microsoft Patch Tuesday for February 2025 — Snort rules and prominent vulnerabilities
Microsoft has released its monthly security update for February of 2025 which includes 63 vulnerabilities affecting a range of products, including 4 that Microsoft marked as “critical” and one marked as "moderate."
There are two notable "critical" vulnerabilities. The first is CVE-2025-21376 , which is a remote code execution (RCE) vulnerability affecting the Windows Lightweight Directory Access Protocol (LDAP). This vulnerability is a remote unauthenticated Out-of-bounds Write (OOBW) caused by a race condition in LDAP and could potentially result in arbitrary code execution in the Local Security Authority Subsystem Service (lsass.exe). This is a process in the Microsoft Windows operating systems tha
Qualys
Microsoft and Adobe Patch Tuesday, February 2025 Security Update Review
blogs_qualys·2025-02-11
Microsoft and Adobe Patch Tuesday, February 2025 Security Update Review
## Table of Contents
Microsoft Patch Tuesday for February 2025
Adobe Patches for February 2025
Zero-day Vulnerabilities Patched in February Patch Tuesday Edition
Critical Severity Vulnerabilities Patched in February Patch Tuesday Edition
Other Microsoft Vulnerability Highlights
Microsoft Release Summary
Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
Rapid Response withPatch Management (PM)
Qualys Monthly Webinar Series
As the second Patch Tuesday of 2025 arrives, Microsoft has released crucial updates to strengthen cybersecurity defenses. Let’s explore the highlights and what they mean for users.
## Microsoft Patch Tuesday for February 2025
Microsoft Patch’s Tuesday, February 2025 edition addressed 67 vulnerabilities, including t
Qualys
Microsoft and Adobe Patch Tuesday, February 2025 Security Update Review | Qualys
blogs_qualys·2025-02-11
Microsoft and Adobe Patch Tuesday, February 2025 Security Update Review | Qualys
#### Table of Contents
- Microsoft Patch Tuesday for February 2025
- Adobe Patches for February 2025
- Zero-day Vulnerabilities Patched in February Patch Tuesday Edition
- Critical Severity Vulnerabilities Patched in February Patch Tuesday Edition
- Other Microsoft Vulnerability Highlights
- Microsoft Release Summary
- Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
- Rapid Response withPatch Management (PM)
- Qualys Monthly Webinar Series
As the second Patch Tuesday of 2025 arrives, Microsoft has released crucial updates to strengthen cybersecurity defenses. Let’s explore the highlights and what they mean for users.
## Microsoft Patch Tuesday for February 2025
Microsoft Patch’s Tuesday, February 2025 edition addressed 67 vulnerabilities,
Bleepingcomputer
Microsoft February 2025 Patch Tuesday fixes 4 zero-days, 55 flaws
blogs_bleepingcomputer·2025-02-11·CVSS 7.1
[HIGH] Microsoft February 2025 Patch Tuesday fixes 4 zero-days, 55 flaws
## Microsoft February 2025 Patch Tuesday fixes 4 zero-days, 55 flaws
## Lawrence Abrams
19 Elevation of Privilege Vulnerabilities
2 Security Feature Bypass Vulnerabilities
22 Remote Code Execution Vulnerabilities
1 Information Disclosure Vulnerabilities
9 Denial of Service Vulnerabilities
3 Spoofing Vulnerabilities
The above numbers do not include a critical Microsoft Dynamics 365 Sales elevation of privileges flaw and 10 Microsoft Edge vulnerabilities fixed on February 6.
To learn more about the non-security updates released today, you can review our dedicated articles on the Windows 11 KB5051987 & KB5051989 cumulative updates and the Windows 10 KB5051974 update .
## Two actively exploited zero-day disclosed
This month's Patch Tuesday fixes two actively exploited and two public
Tenable
Microsoft’s February 2025 Patch Tuesday Addresses 55 CVEs (CVE-2025-21418, CVE-2025-21391)
blogs_tenable·2025-02-11·CVSS 7.1
[HIGH] Microsoft’s February 2025 Patch Tuesday Addresses 55 CVEs (CVE-2025-21418, CVE-2025-21391)
## Cloud Exposure
Tenable Cloud Security (CNAPP) Request a demo
Tenable Cloud Vulnerability Management Request a demo
Tenable CIEM Request a demo
Secure your cloud
## Vulnerability Exposure
Tenable Vulnerability Management Try for free
Tenable Security Center Request a demo
Tenable Web App Scanning Try for free
Tenable Patch Management Request a demo
Tenable Enclave Security Request a demo
Tenable Attack Surface Management Request a demo
Tenable Nessus Try for free
## AI Exposure
Tenable AI Exposure Request a demo
## OT/IoT Exposure
Tenable OT Security Request a demo
## Identity Exposure
Tenable Identity Exposure Request a demo
## Business needs
Active Directory
AI Security Posture Management (AI-SPM)
AWS security
Azure security
Cloud Security Posture Man
Crowdstrike
February 2025 Patch Tuesday: Updates and Analysis
blogs_crowdstrike·CVSS 7.5
CVE-2026-20929 [HIGH] February 2025 Patch Tuesday: Updates and Analysis
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2025-02-11
Published
2025-02-11
Added to CISA KEV
Exploited in the wild