CVE-2026-72940: CWE-122: Heap-based Buffer Overflow in Microsoft Windows 11 version 23H2
Description
CVE-2026-72940 is a heap-based buffer overflow vulnerability in the Windows Schannel component affecting Windows 11 version 23H2 and related builds. This flaw allows an unauthorized attacker to execute code remotely over a network. The vulnerability has a high severity with a CVSS score of 8.8. Microsoft has released an official fix to address this issue.
CVSS v3.1
Score 8.8high
Affected software
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 (CVE-2026-72940) involves a heap-based buffer overflow in the Windows Schannel security package, which is part of Windows 11 version 23H2 and several related builds. An attacker can exploit this flaw remotely without privileges and with low attack complexity, potentially executing arbitrary code, causing full confidentiality, integrity, and availability impact. The vulnerability is officially patched by Microsoft, as detailed in their security update guide.
Potential Impact
Successful exploitation allows remote code execution without requiring privileges, potentially leading to complete system compromise including full confidentiality, integrity, and availability loss. This represents a critical risk to affected systems if unpatched.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security updates provided by Microsoft to remediate this vulnerability. No additional mitigation steps are indicated beyond applying the official patch.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-08-10T18:14:23.516Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72940","vendor":"Microsoft"}]
Threat ID: 6aa04544acd9273b49fa9cb2
Added to database: 09/08/2026, 17:26:28 UTC
Last enriched: 10/16/2026, 21:45:34 UTC
Last updated: 10/22/2026, 01:15:25 UTC
Views: 23
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