SYSTEM privilege escalation via AFD heap overflow
Published Feb 11, 2025 · Updated Feb 26, 2026
Heap-based buffer overflow in Microsoft Windows AFD for WinSock allows local users with low privileges to gain SYSTEM privileges. Microsoft identifies the affected locus as the Ancillary Function Driver but has not disclosed which AFD operation mishandles attacker-controlled data or how the heap buffer is overrun. Exploitation requires local low-privilege access and no user interaction; successful attacks execute with SYSTEM authority, and CISA reports active exploitation.
Summary
What happened
Heap-based buffer overflow in Microsoft Windows AFD for WinSock allows local users with low privileges to gain SYSTEM privileges. Microsoft identifies the affected locus as the Ancillary Function Driver but has not disclosed which AFD operation mishandles attacker-controlled data or how the heap buffer is overrun. Exploitation requires local low-privilege access and no user interaction; successful attacks execute with SYSTEM authority, and CISA reports active exploitation.
The record
- CVE
- CVE-2025-21418
- Published
- Feb 11, 2025
- Updated
- Feb 26, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- CWE-122, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 11, 2025CVE publishedPublication date reported by the CVE source.
- Feb 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.10240.0 <10.0.10240.20915
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Reported exploitation
- CISA Known Exploited Vulnerabilities Catalog entryknown exploited catalog
Technologies
Your stack
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Your stack
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