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Windows Credential Guard CVE-2026-72958

| EUVDEUVD-2026-73115 HIGH
Double Free (CWE-415)
2026-09-08 secure@microsoft.com GHSA-xx88-v4cq-w4wj
8.2
CVSS 3.1 · Vendor: microsoft
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Attack ChainAIDerived

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

  1. Access
    Attain local administrator privileges on target
  2. Delivery
    Access Credential Guard component API or driver interface
  3. Exploit
    Trigger double-free in isolated LSA heap
  4. Execution
    Corrupt heap metadata to overwrite security descriptor or function pointer
  5. Persist
    Escape VBS isolation boundary
  6. Impact
    Extract protected NTLM hashes or Kerberos tickets from isolated store

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Double free prevention
Exploitation Conditions

Exploitation requires that the attacker already holds high-privileged (administrator or equivalent) local access to the target Windows system - the CVSS PR:H metric confirms this. Windows Credential Guard must be enabled on the target, which requires compatible hardware (UEFI, Secure Boot, Hyper-V, IOMMU) and is a non-default configuration on most consumer deployments but increasingly common in enterprise Windows 11 and Server 2025 deployments. Exploitation is purely local (AV:L); no network path to the vulnerable component exists. Attack complexity is low (AC:L) once prerequisites are met, meaning no race conditions or special timing is needed beyond holding the required privilege level.

Impact

The CVSS 8.2 score is driven by the scope change and high impact across all three pillars (C:H/I:H/A:H), which is appropriate given that Credential Guard isolation is the target. However, the PR:H prerequisite substantially reduces real-world risk: the attacker must already have administrator or kernel-level access to trigger the double free, meaning this is a post-compromise, privilege-boundary-crossing primitive rather than an initial access vector. No public exploit code has been disclosed and this CVE does not appear in the CISA KEV catalog, making opportunistic mass exploitation unlikely. The realistic threat is an insider or a post-exploitation actor seeking to extract credential material that Credential Guard specifically protects - even a mid-sized enterprise IT operation that has deployed Credential Guard on Windows 11 endpoints or Server 2025 should treat this as a priority patch, since the whole value of Credential Guard is eliminating credential theft after initial compromise. EPSS data is not available in the provided intelligence; given no KEV and no known POC, actual exploitation probability is assessed as low in the near term.

Exploit ScenarioDerived

An attacker who has gained administrative access to a Windows 11 or Server 2025 endpoint - for example, through credential theft or lateral movement - triggers the double-free defect in the Credential Guard component to corrupt the isolated LSA heap. This allows the attacker to escape the VBS-protected boundary and access NTLM hash or Kerberos ticket material that Credential Guard was specifically designed to shield, enabling subsequent pass-the-hash or pass-the-ticket attacks against other network resources. No public proof-of-concept code has been identified at time of analysis.

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

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AnalysisAIv1 – Sep 08, 2026

Privilege escalation through a double-free memory corruption flaw in Windows Credential Guard affects Windows 11 (versions 24H2, 25H2, 26H1) and Windows Server 2025. An attacker who already holds elevated local privileges on a target system can exploit the CWE-415 defect to escape the Credential Guard security boundary, achieving scope change with high confidentiality, integrity, and availability impact on protected credential stores. No public exploit code and no CISA KEV listing are present at time of analysis; Microsoft has released patches as part of its update guidance.

RemediationAI

Apply Microsoft's security update immediately: Windows 11 24H2 and Server 2025 should be upgraded to build 10.0.26100.33438 or later; Windows 11 25H2 to 10.0.26200.9445 or later; Windows 11 26H1 to 10.0.28000.2954 or later. The patch is available via Windows Update and Windows Server Update Services (WSUS) as documented in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72958. If immediate patching is not possible, consider restricting local administrator and kernel-level access on systems running Credential Guard through privilege access workstation (PAW) controls and tiered administration models, since exploitation requires PR:H. Disabling Credential Guard entirely as a workaround is counterproductive as it removes the protection the patch is designed to preserve.

Affected VersionsENISA

Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.9445
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33438
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9445
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.2954
Windows Server 2025 10.0.26100.0 <10.0.26100.33438

Affected Packages

euvd windows_11_version_24h2 fix: 10.0.26100.9445
euvd windows_11_version_25h2 fix: 10.0.26200.9445
euvd windows_11_version_26h1 fix: 10.0.28000.2954
euvd windows_server_2025 fix: 10.0.26100.33438
euvd windows_server_2025_server_core_installation fix: 10.0.26100.33438

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 5 packages in euvd

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

Technical ContextAI · show details

Windows Credential Guard is a virtualization-based security (VBS) feature introduced to isolate NTLM and Kerberos credential material in a Trusted Execution Environment (Isolated LSA process). CWE-415 (Double Free) occurs when heap memory is released twice; in a high-integrity VBS context this can corrupt the hypervisor-backed heap and allow an attacker to overwrite function pointers or security descriptors, ultimately escaping the isolated environment boundary. The scope change (S:C) in the CVSS vector reflects that successful exploitation crosses from the Credential Guard isolated context into the broader host OS security domain. Affected CPE ranges span Windows 11 builds 10.0.26100.x and 10.0.26200.x and 10.0.28000.x, as well as Windows Server 2025 at 10.0.26100.x, confirmed via EUVD-2026-73115 version table.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 8.2 HIGH
AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
vuln.today AI 8.2 HIGH

Local-only exploitation requiring administrator privileges (PR:H) with scope change escaping Credential Guard VBS boundary; all impacts high once boundary is crossed.

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

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

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

Lifecycle Timeline

2
Patch available
Sep 08, 2026 - 18:35 EUVD
CVE Published
Sep 08, 2026 - 18:20 nvd
HIGH 8.2

DescriptionCVE.org

Double free in Windows Credential Guard allows an authorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

Credential Guard in Windows 11 (versions 24H2, 25H2, 26H1) and Windows Server 2025 contains a memory corruption flaw enabling local administrators to escape the credential-protection boundary and access sensitive authentication data. Successful exploitation could expose organization-wide authentication materials to compromise, facilitating lateral movement and privilege escalation across enterprise infrastructure. Microsoft has released patches that organizations must deploy urgently.

Business Impact: High
Compensating Controls

Patch available per vendor advisory.

Threat Intelligence Overview

EPSS Score
0.3%
Top 75% exploitable
Prevalence
High
Windows 11 and Server 2025 are widely deployed enterprise platforms
Threat Intel
1
1 sources
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Unlikely
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

41
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +41
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0
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