What is the CVSS score of CVE-2026-20853?

CVE-2026-20853 has a CVSS 3.1 base score of 7.4 (High). CVSS vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

How to fix or mitigate CVE-2026-20853?

Within 7 days: Identify all affected systems and apply vendor patches promptly. Monitor vendor channels for patch availability.

Windows 10 1607 CVE-2026-20853

HIGH

Race Condition (CWE-362)

2026-01-13 secure@microsoft.com

Authentication Bypass Race Condition Microsoft Windows 10 1607 Windows 10 1809 Windows 10 21h2 Windows 10 22h2 Windows 11 23h2 Windows 11 24h2 Windows 11 25h2

7.4

CVSS 3.1 · Vendor: microsoft

View

Attack ChainAIDerived

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

Access

Access local system
Exploit

Trigger race condition in WalletService shared resource
Execution

Bypass synchronization mechanism
Impact

Escalate privileges to SYSTEM

Vulnerability Assessment

Weakness	CWE CWE-362 OWASP Top 10:2025 A06:2025 - Insecure Design ASVS 5.0 V15 - Secure Coding and Architecture Concurrency control, locking MITRE ATT&CK 1 technique across 1 tactic: Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	Local system access required. Windows WalletService must be running with concurrent access to shared resources. Race condition window requires precise timing during WalletService operations (high complexity exploitation)
Impact	CVSS 7.4 (HIGH). Attack vector: Local. Complexity: High. Privileges required: None. User interaction: None. Exploitation no authentication required. Exploitable via local access.
Exploit ScenarioDerived	An attacker without authentication could exploit this vulnerability to compromise the affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Windows WalletService contains a race condition that permits local privilege escalation on Windows 10 and Windows 11 systems. An unauthenticated attacker with local access can exploit improper synchronization of shared resources to gain elevated privileges. No patch is currently available for this vulnerability.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 7.4

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows WalletService allows an unauthorized attacker to elevate privileges locally. [CVSS 7.4 HIGH]

RemediationAI

Monitor vendor advisories for a patch.

Affected Packages

microsoft windows_10_version_1607_10_0_14393_8783 fix: Windows 10 Version 1607 for 32-bit Systems 10.0.14393.8783, Windows 10 Version 1607 for x64-based Systems 10.0.14393.8783

microsoft windows_10_version_1809_10_0_17763_8276 fix: Windows 10 Version 1809 for 32-bit Systems 10.0.17763.8276, Windows 10 Version 1809 for x64-based Systems 10.0.17763.8276

microsoft windows_10_version_21h2_10_0_19044_6809 fix: Windows 10 Version 21H2 for 32-bit Systems 10.0.19044.6809, Windows 10 Version 21H2 for ARM64-based Systems 10.0.19044.6809, Windows 10 Version 21H2 for x64-based Systems 10.0.19044.6809

microsoft windows_10_version_22h2_10_0_19045_6809 fix: Windows 10 Version 22H2 for 32-bit Systems 10.0.19045.6809, Windows 10 Version 22H2 for ARM64-based Systems 10.0.19045.6809, Windows 10 Version 22H2 for x64-based Systems 10.0.19045.6809

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

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 7 packages in microsoft

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

Technical ContextAI · show details

Classified as CWE-362 (Race Condition). Affects Windows 10 1607. Concurrent execution using shared resource with improper synchronization ('race condition') in Windows WalletService allows an unauthorized attacker to elevate privileges locally.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 7.4 HIGH

AV:L/AC:H/PR:N/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

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows WalletService allows an unauthorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

CVE-2026-20853 presents moderate security risk, a race condition vulnerability rated CVSS 7.4. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: Moderate

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score

0.0%

Top 93% 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 HIGH

CISA KEV No

Public POC No

EPSS 0.0%

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

Exploitation· derived

None

System Exposure· derived

Small

Automatable· derived

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +37

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Race Condition MEDIUM

Race conditions occur when multiple concurrent requests exploit the brief time gap between checking a condition and acting upon it (TOCTOU - Time of Check, Time of Use).