Skip to main content

Windows 11 23h2 CVE-2026-20876

MEDIUM
Heap-based Buffer Overflow (CWE-122)
2026-01-13 secure@microsoft.com
Buffer Overflow Heap Overflow Microsoft Windows 11 23h2 Windows 11 24h2 Windows 11 25h2 Windows Server 2022 23h2 Windows Server 2025
6.7
CVSS 3.1 · Vendor: microsoft
View

Vulnerability Assessment

Weakness
CWE
CWE-122
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Heap buffer bounds checking
MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Sign in to read
Impact

CVSS 6.7 (MEDIUM). Attack vector: Local. Complexity: Low. Privileges required: High. User interaction: None. Exploitable via local access.
Exploit ScenarioDerived

An attacker could exploit this vulnerability to compromise the affected system.
This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Mar 12, 2026

Privilege escalation in Windows Virtualization-Based Security (VBS) Enclave affects Windows 11 and Windows Server 2022 through a heap-based buffer overflow in memory management. An authenticated local attacker with high privileges can exploit this vulnerability to gain unauthorized system-level access. No patch is currently available for this medium-severity vulnerability (CVSS 6.7).

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 21:54 CVSS 6.7

Heap-based buffer overflow in Windows Virtualization-Based Security (VBS) Enclave allows an authorized attacker to elevate privileges locally. [CVSS 6.7 MEDIUM]

RemediationAI

Monitor vendor advisories for a patch. Enable ASLR, DEP/NX, and stack canaries where possible.

Affected Packages

microsoft windows_11_version_23h2_10_0_22631_6491 fix: Windows 11 Version 23H2 for ARM64-based Systems 10.0.22631.6491, Windows 11 Version 23H2 for x64-based Systems 10.0.22631.6491
microsoft windows_11_version_24h2_10_0_26100_7623 fix: Windows 11 Version 24H2 for ARM64-based Systems 10.0.26100.7623, Windows 11 Version 24H2 for x64-based Systems 10.0.26100.7623
microsoft windows_11_version_25h2_10_0_26200_7623 fix: Windows 11 Version 25H2 for ARM64-based Systems 10.0.26200.7623, Windows 11 Version 25H2 for x64-based Systems 10.0.26200.7623
microsoft windows_server_2022_23h2_edition_10_0_25398_2092 fix: Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2092
microsoft windows_server_2025_10_0_26100_32230 fix: Windows Server 2025 10.0.26100.32230, Windows Server 2025 (Server Core installation) 10.0.26100.32230

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 5 packages in microsoft

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Sign in to check
Technical ContextAI · show details

Classified as CWE-122 (Heap-based Buffer Overflow). Affects Windows 11 23H2. Heap-based buffer overflow in Windows Virtualization-Based Security (VBS) Enclave allows an authorized attacker to elevate privileges locally.

Know when Windows 11 23h2 gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources
Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

Vendor (microsoft) PRIMARY 6.7 MEDIUM
AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Primary rating from Vendor (microsoft) · only source for this CVE.

CVSS VectorVendor: microsoft

Attack Vector
Local
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

Heap-based buffer overflow in Windows Virtualization-Based Security (VBS) Enclave allows an authorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

CVE-2026-20876 presents notable security risk, a heap-based buffer overflow vulnerability rated CVSS 6.7. Exploitation could cause memory corruption or application crashes. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Moderate
Compensating Controls

Apply vendor patch. If patching is delayed: enable ASLR/DEP, apply network segmentation.

Threat Intelligence Overview

EPSS Score
0.0%
Top 89% exploitable
Data Quality
3 sources
Confidence: Low
NVD CVE.org EPSS VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No

Priority Score

34
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +34
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Heap Overflow HIGH

A heap overflow occurs when a program writes data beyond the bounds of a buffer allocated in the heap memory region.

Affected Products (CPE)CVE.org

cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*

More in Windows 11 23h2

View all
CVE-2024-21412 HIGH POC
8.1 Feb 13

Internet Shortcut Files Security Feature Bypass Vulnerability. Rated high severity (CVSS 8.1), this vulnerability is rem
CVE-2024-30088 HIGH POC
7.0 Jun 11

Windows Kernel contains a TOCTOU race condition vulnerability allowing local privilege escalation, exploited by the OilR
CVE-2025-33053 HIGH POC
8.8 Jun 10

Windows Internet Shortcut Files (.url) contain an external control vulnerability (CVE-2025-33053, CVSS 8.8) that enables
CVE-2025-33073 HIGH POC
8.8 Jun 10

Windows SMB contains an improper access control vulnerability (CVE-2025-33073, CVSS 8.8) enabling authenticated attacker
CVE-2024-21338 HIGH POC
7.8 Feb 13

Windows Kernel Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack co
CVE-2013-3900 MEDIUM
5.5 Dec 11

Why is Microsoft republishing a CVE from 2013? We are republishing CVE-2013-3900 in the Security Update Guide to update

CVE-2025-21293 HIGH POC
8.8 Jan 14

Active Directory Domain Services contains an elevation of privilege vulnerability that allows authenticated domain users
CVE-2024-35250 HIGH POC
7.8 Jun 11

Windows Kernel-Mode Driver Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is l
CVE-2024-43461 HIGH
8.8 Sep 10

Windows MSHTML Platform Spoofing Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitab
CVE-2025-30397 HIGH POC
7.5 May 13

Microsoft Scripting Engine contains a type confusion vulnerability allowing unauthorized remote code execution over the

CVE-2024-49039 HIGH POC
8.8 Nov 12

Windows Task Scheduler Elevation of Privilege Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is low a
CVE-2026-96951 HIGH POC
8.8 Oct 13

Command injection in the Windows Shell lets remote, unauthenticated attackers bypass a Windows security feature and then

Same weakness CWE-122 – Heap-based Buffer Overflow

View all
CVE-2023-4911 HIGH POC
7.8
CVE-2023-27997 CRITICAL
9.8
CVE-2026-94127 CRITICAL POC
9.3
CVE-2025-25249 CRITICAL POC
9.8
CVE-2026-85880 HIGH POC
7.8
CVE-2025-24985 HIGH POC
7.8
CVE-2026-53362 HIGH POC
7.8
CVE-2025-21418 HIGH
7.8

Same technique Buffer Overflow

View all
CVE-2017-7269 CRITICAL POC
9.8
CVE-2015-5119 CRITICAL POC
9.8
CVE-2015-3113 CRITICAL POC
9.8
CVE-2011-2462 CRITICAL POC
9.8
CVE-2020-0796 CRITICAL POC
10.0
CVE-2019-11043 CRITICAL POC
9.8
CVE-2009-0927 HIGH POC
8.8
CVE-2012-1889 HIGH POC
8.8

References

Advisories & patches
ADVISORY https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20876 ADVISORY https://vuldb.com/vuln/340806

Search Externally

GitHub PoC Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy