CVE-2026-69821: CWE-116: Improper Encoding or Escaping of Output in Microsoft Windows 10 Version 1607
Description
CVE-2026-69821 is a high-severity vulnerability in Microsoft Windows 10 Version 1607 and related versions. It involves improper encoding or escaping of output in Active Directory Certificate Services (AD CS), which allows an authorized attacker to elevate privileges locally. The vulnerability affects multiple Windows 10 builds and some earlier versions. An official fix is available from Microsoft.
CVSS v3.1
Score 7.8high
Affected software
Microsoft
Windows 10 Version 1607
Microsoft
Windows 10 Version 1809
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 (CVE-2026-69821) is due to improper encoding or escaping of output in Active Directory Certificate Services (AD CS) on affected Windows versions. This flaw enables an authorized attacker to perform local privilege escalation. The CVSS 3.1 base score is 7.8, indicating high severity, with impact on confidentiality, integrity, and availability. The vulnerability affects Windows 10 Version 1607 and other specified builds prior to certain patch levels. Microsoft has released an official fix for this issue.
Potential Impact
An authorized attacker with local access can exploit this vulnerability to elevate privileges, potentially gaining higher-level access than intended. This can compromise system confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security updates provided by Microsoft for the affected Windows versions as detailed in the vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69821. No additional mitigation steps are indicated by the vendor.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-08-03T22:50:31.851Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69821","vendor":"Microsoft"}]
Threat ID: 6aa04531acd9273b49fa9a1b
Added to database: 09/08/2026, 17:26:09 UTC
Last enriched: 10/16/2026, 21:35:40 UTC
Last updated: 10/21/2026, 13:40:31 UTC
Views: 30
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