CVE-2026-69921: CWE-122: Heap-based Buffer Overflow in Microsoft Windows 10 Version 21H2
Description
CVE-2026-69921 is a heap-based buffer overflow vulnerability in the Windows Print Spooler components of Microsoft Windows 10 Version 21H2. This flaw allows an authorized local attacker to elevate privileges on the affected system. The vulnerability has a high severity rating with a CVSS score of 7.8. Official patches are available from Microsoft to address this issue.
CVSS v3.1
Score 7.8high
Affected software
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 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 Windows Print Spooler components on Windows 10 Version 21H2. An attacker with local authorized access can exploit this flaw to elevate their privileges, potentially gaining higher system rights. The vulnerability is tracked as CVE-2026-69921 and is classified under CWE-122 (Heap-based Buffer Overflow). Multiple specific Windows 10 builds are affected, and Microsoft has issued official fixes for these versions.
Potential Impact
Successful exploitation of this vulnerability allows an authorized local attacker to elevate their privileges, potentially leading to full control over the affected system. The impact includes confidentiality, integrity, and availability being fully compromised (high impact on all three). There are no known exploits in the wild at this time.
Mitigation Recommendations
Microsoft has released official patches to address this vulnerability. Users and administrators should apply the available updates for their specific Windows 10 versions as listed in the affected versions to remediate this issue. Since an official fix is available, applying the patch is the recommended mitigation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-08-03T22:59:57.548Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69921","vendor":"Microsoft"}]
Threat ID: 6aa04537acd9273b49fa9ae2
Added to database: 09/08/2026, 17:26:15 UTC
Last enriched: 10/16/2026, 21:39:13 UTC
Last updated: 10/23/2026, 15:10:14 UTC
Views: 35
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