CVE-2026-87699: CWE-122: Heap-based Buffer Overflow in Microsoft Windows 10 Version 1607
Description
Heap-based buffer overflow in Winlogon allows an authorized attacker to elevate privileges locally.
CVSS v3.1
Score 7.8high
Affected software
Microsoft
Windows 10 Version 1607
Microsoft
Windows 10 Version 1809
Microsoft
Windows 10 Version 21H2
Microsoft
Windows 10 Version 22H2
Microsoft
Windows 11 version 23H2
Microsoft
Windows 11 Version 23H2
Microsoft
Windows 11 Version 24H2
Microsoft
Windows 11 Version 25H2
Microsoft
Windows 11 version 26H1
Microsoft
Windows 11 Version 26H2
Microsoft
Windows Server 2012
Microsoft
Windows Server 2012 (Server Core installation)
Microsoft
Windows Server 2012 R2
Microsoft
Windows Server 2012 R2 (Server Core installation)
Microsoft
Windows Server 2016
Microsoft
Windows Server 2016 (Server Core installation)
Microsoft
Windows Server 2019
Microsoft
Windows Server 2019 (Server Core installation)
Microsoft
Windows Server 2022
Microsoft
Windows Server 2025
Microsoft
Windows Server 2025 (Server Core installation)
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves a heap-based buffer overflow in the Winlogon process of Microsoft Windows 10 Version 1607 and other specified builds. An authorized local attacker can exploit this flaw to elevate their privileges, potentially gaining higher-level access on the system. The vulnerability is tracked as CWE-122 and has a CVSS v3.1 base score of 7.8, indicating high severity. Microsoft has published an official security update to remediate this issue.
Potential Impact
Successful exploitation allows an authorized local attacker to elevate privileges, potentially gaining administrative rights or equivalent on the affected Windows system. This could lead to unauthorized actions at a higher privilege level, impacting confidentiality, integrity, and availability.
Mitigation Recommendations
Microsoft has released an official security update that fixes this vulnerability. Users and administrators should apply the provided patches as soon as possible to mitigate the risk. Since an official fix is available, updating to the fixed versions is the recommended remediation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-09-08T23:57:53.797Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87699","vendor":"Microsoft"}]
Threat ID: 6ace85512cdf04f6569ff31b
Added to database: 10/13/2026, 19:24:01 UTC
Last enriched: 10/14/2026, 02:19:59 UTC
Last updated: 10/14/2026, 04:19:18 UTC
Views: 3
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