Skip to main content

Windows VBS Enclave CVE-2026-96914

| EUVDEUVD-2026-100245 HIGH
Heap-based Buffer Overflow (CWE-122)
2026-10-13 secure@microsoft.com GHSA-gg23-vp4x-hqwv
8.8
CVSS 3.1 · Vendor: microsoft
View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Gain local authenticated access
  2. Delivery
    Invoke VBS enclave interface with crafted size
  3. Exploit
    Trigger integer overflow into heap buffer overflow
  4. Execution
    Execute code across enclave trust boundary
  5. Impact
    Elevate to compromise VBS-protected context

Vulnerability Assessment

Weakness
CWE
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.

Exploitation Conditions

Exploitation requires the attacker to already possess local, authenticated code-execution on the target host (CVSS PR:L, AV:L) and to reach the Windows Virtualization-Based Security (VBS) Enclave code path - so VBS must be enabled/in use on the system, which is the limiting factor. No user interaction is needed (UI:N) and attack complexity is low (AC:L). The required prerequisite - an existing low-privileged foothold plus a VBS-enabled configuration - is what constrains realistic exploitation; this is a privilege-escalation primitive, not a remote entry point. Patched builds per EUVD must be absent (e.g., below 10.0.26100.33650 on Server 2025, below 10.0.26200.9711 on Windows 11 25H2).

Impact

This is a locally-exploitable elevation-of-privilege flaw with a provided CVSS 3.1 vector of AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H (base 8.8), meaning low-complexity exploitation by an already-authenticated local user with no user interaction, and a changed scope reflecting that compromise of the VBS enclave crosses a trust boundary into the protected/secure environment. The signals are internally consistent but point to moderate rather than emergency priority: CISA SSVC lists Exploitation as 'none' and Automatable as 'no' while rating Technical Impact as 'total', and the CVE is NOT in CISA KEV, with no public exploit identified at time of analysis - so the high score is driven by impact (full enclave compromise), not by demonstrated real-world exploitation. The AV:L/PR:L combination means an attacker must first obtain code execution as a local authenticated user, which materially limits mass exploitation but makes this a valuable second-stage/privilege-escalation primitive for an attacker who already has a foothold. No EPSS score was supplied in the input, so exploitation probability cannot be quantified here; absence of EPSS/KEV/POC data should be treated as 'unknown', not as evidence of low risk.

Exploit ScenarioDerived

An attacker who has already achieved low-privileged code execution on a Windows host (e.g., via phishing or a compromised standard user account) invokes the vulnerable VBS Enclave interface with crafted input that triggers an integer overflow leading to a heap buffer overflow (CWE-122). Because the CVSS scope is changed (S:C), successful exploitation escapes the normal process boundary and compromises the Virtualization-Based Security enclave, yielding full confidentiality, integrity, and availability impact. No public proof-of-concept exploit has been identified at time of analysis, and CISA SSVC currently rates exploitation status as 'none'.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.3% exploitation probability (EPSS)

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

Alert me

AnalysisAIv1 – Oct 13, 2026

Local privilege escalation in the Windows Virtualization-Based Security (VBS) Enclave allows an authenticated attacker who already holds low-privileged code execution on a VBS-enabled host to cross the enclave trust boundary and gain high-integrity code execution, carrying a CVSS 3.1 base score of 8.8 (AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H). Patched builds are absent across Windows 10 (1607 through 22H2), Windows 11 (23H2 through 26H2), and Windows Server 2016 through 2025, including Server Core installations. No public exploit code or confirmed active exploitation has been identified at time of analysis, with CISA's SSVC assessment recording exploitation as none and automatable as no.

RemediationAI

Vendor-released patches are available; update every affected host to at or above the fixed builds listed by Microsoft's update guide and the EUVD entry - for example 10.0.26100.33650 for Windows Server 2025 and Windows 11 24H2, 10.0.26200.9711 for Windows 11 25H2, 10.0.26300.9711 for Windows 11 26H2, 10.0.28000.3231 for Windows 11 26H1, 10.0.22631.7652 for Windows 11 23H2, 10.0.20348.5761 for Windows Server 2022, 10.0.17763.9376 for Windows Server 2019, 10.0.14393.9612 for Windows Server 2016, and 10.0.19044.7807 for Windows 10 21H2/22H2. Because the issue is a local, post-foothold privilege-escalation primitive rather than a remote entry point, patching should be combined with restricting interactive and RDP logon on high-value servers to reduce the chance an attacker ever obtains the required local low-privileged context, and with endpoint monitoring for unexpected access to VBS/enclave-related APIs. Where VBS is not operationally required, disabling it (which also turns off Credential Guard and HVCI) removes the vulnerable enclave attack surface, but this is a genuine trade-off: it weakens defenses against credential theft and kernel-level exploitation, so it should be limited to systems with an explicit documented justification and only until patching is completed. Disabling VBS is not a substitute for installing the vendor fix, and no public exploit code exists at time of analysis to validate alternative mitigations.

Affected VersionsENISA

Windows Server 2019 (Server Core installation) 10.0.17763.0 <10.0.17763.9376
Windows Server 2022 10.0.20348.0 <10.0.20348.5761
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33650
Windows 10 Version 1607 10.0.14393.0 <10.0.14393.9612
Windows Server 2025 10.0.26100.0 <10.0.26100.33650
Windows 10 Version 22H2 10.0.19045.0 <10.0.19044.7807
Windows 11 Version 26H2 10.0.26300.0 <10.0.26300.9711
Windows Server 2019 10.0.17763.0 <10.0.17763.9376
Windows 10 Version 21H2 10.0.19044.0 <10.0.19044.7807
Windows Server 2016 10.0.14393.0 <10.0.14393.9612
Windows 10 Version 1809 10.0.17763.0 <10.0.17763.9376
Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.9711
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9711
Windows Server 2016 (Server Core installation) 10.0.14393.0 <10.0.14393.9612
Windows 11 Version 23H2 10.0.22631.0 <10.0.22631.7652
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.3231

Affected Packages

euvd windows_10_version_1607 fix: 10.0.14393.9612
euvd windows_10_version_1809 fix: 10.0.17763.9376
euvd windows_10_version_21h2 fix: 10.0.19044.7807
euvd windows_10_version_22h2 fix: 10.0.19044.7807
euvd windows_11_version_23h2 fix: 10.0.22631.7652
euvd windows_11_version_24h2 fix: 10.0.26100.9711
euvd windows_11_version_25h2 fix: 10.0.26200.9711
euvd windows_11_version_26h1 fix: 10.0.28000.3231
euvd windows_11_version_26h2 fix: 10.0.26300.9711
euvd windows_server_2016 fix: 10.0.14393.9612
euvd windows_server_2016_server_core_installation fix: 10.0.14393.9612
euvd windows_server_2019 fix: 10.0.17763.9376
euvd windows_server_2019_server_core_installation fix: 10.0.17763.9376
euvd windows_server_2022 fix: 10.0.20348.5761
euvd windows_server_2025 fix: 10.0.26100.33650
euvd windows_server_2025_server_core_installation fix: 10.0.26100.33650

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 16 packages in euvd

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

Technical ContextAI · show details

Virtualization-Based Security on Windows uses the Hyper-V hypervisor to carve out isolated execution environments - VBS enclaves - that host security-sensitive operations such as Credential Guard, HVCI, and protected key material, placing them outside the reach of normal user-mode and even kernel-mode code. The flaw is tracked as CWE-122 (heap-based buffer overflow) and is described as an integer overflow or wraparound, a classic pairing in which an arithmetic miscalculation of a buffer or allocation size inside the enclave handling path produces an undersized heap allocation that is subsequently written past its bounds. The changed-scope metric (S:C) reflects that the vulnerable component - the VBS enclave - is a distinct security boundary from the calling user-mode context, so a successful exploit crosses a trust boundary rather than staying within the same privilege domain. Because the CVSS vector carries AV:L and PR:L, the attacker must already have local access and a valid low-privileged account, and VBS must be enabled or in active use on the target, which is the principal configuration constraint on realistic exploitation.

Know when Windows 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

No credit card · 7-day full trial

Severity by source

Vendor (microsoft) PRIMARY 8.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
vuln.today AI 8.8 HIGH

Local vector and prior low-privileged access give AV:L/PR:L; low complexity AC:L; crossing the VBS enclave trust boundary is S:C with total C/I/A impact.

3.1 AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

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

Lifecycle Timeline

2
Patch available
Oct 13, 2026 - 20:20 EUVD
CVE Published
Oct 13, 2026 - 19:22 cve.org
HIGH 8.8

DescriptionCVE.org

Integer overflow or wraparound in Windows Virtualization-Based Security (VBS) Enclave allows an authorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

A high-severity local privilege-escalation flaw in Windows Virtualization-Based Security (VBS) Enclave affects Windows 10, Windows 11, and Windows Server 2016 through 2025, including Server Core, allowing an attacker who already has a foothold on a VBS-enabled host to break out of the enclave and operate with high-integrity privileges. Because VBS underpins isolation for credentials, virtualization, and other sensitive workloads on modern Windows endpoints and servers, a successful escalation could let an intruder bypass the very controls leadership relies on to contain a breach. The exposure is broad across the managed Windows estate, and remediation requires coordinated patching rather than a single product upgrade.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 83% exploitable
Prevalence
Ubiquitous
core Windows client and server OS, deployed across nearly all environments
Threat Intel
1
1 sources
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Less Likely
Data Quality
5 sources
Confidence: Medium

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 HIGH
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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

SSVC Decision
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +44
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

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.

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

CVE-2025-52691 CRITICAL POC
10.0 Dec 29

Unauthenticated remote code execution in SmarterTools SmarterMail lets an attacker upload arbitrary files to any locatio

CVE-2019-0803 HIGH POC
7.8 Apr 09

Windows Win32k fails to properly handle objects in memory, allowing local privilege escalation exploited in the wild in

CVE-2020-1472 MEDIUM POC
5.5 Aug 17

A privilege escalation vulnerability (CVSS 5.5). Risk factors: actively exploited (KEV-listed), EPSS 94% exploitation pr

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-2025-13315 CRITICAL POC
9.3 Nov 19

Twonky Server 8.5.2 on Linux and Windows allows unauthenticated access to the admin log file through a web service API b

CVE-2013-10047 CRITICAL POC
9.3 Aug 01

An unrestricted file upload vulnerability exists in MiniWeb HTTP Server <= Build 300 that allows unauthenticated remote

CVE-2012-10030 CRITICAL POC
9.3 Aug 05

FreeFloat FTP Server contains multiple critical design flaws that allow unauthenticated remote attackers to upload arbit

CVE-2025-34101 CRITICAL POC
9.3 Jul 10

Serviio Media Server versions 1.4 through 1.8 on Windows contain an unauthenticated command injection in the /rest/actio

CVE-2025-13316 HIGH POC
8.2 Nov 19

Twonky Server 8.5.2 uses hard-coded cryptographic keys for encrypting the administrator password. Combined with the cred

CVE-2025-34095 CRITICAL POC
9.3 Jul 10

Mako Server versions 2.5 and 2.6 contain an unauthenticated OS command injection via the tutorial interface at examples/

CVE-2025-11953 CRITICAL POC
9.8 Nov 03

React Native Metro Development Server binds to external interfaces by default and contains an OS command injection endpo

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