CVE-2026-83855

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Integer Underflow in Windows WLAN Service Causes DoS

Publication date: 2026-10-13

Last updated on: 2026-10-13

Assigner: Microsoft Corporation

Description

Integer underflow (wrap or wraparound) in Windows WLAN Service allows an unauthorized attacker to deny service over a network.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-13

Last Modified

2026-10-13

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-83855

EUVD

EUVD-2026-99391

Affected Vendors & Products

Vendor	Product	Version / Range
Microsoft	Windows	11 version 23H2 10.0.22631.0
Microsoft	Windows	11 Version 23H2 10.0.22631.0
Microsoft	Windows	11 Version 24H2 10.0.26100.0
Microsoft	Windows	11 Version 25H2 10.0.26200.0
Microsoft	Windows	11 version 26H1 10.0.28000.0
Microsoft	Windows	11 Version 26H2 10.0.26300.0
Microsoft	Windows	Server 2025 10.0.26100.0
Microsoft	Windows	Server 2025 (Server Core installation) 10.0.26100.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-191	The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

Attack-Flow Graph

Executive Summary

This vulnerability is an integer underflow in the Windows WLAN Service. An attacker can exploit it to cause a denial of service over a network without needing authorization.

Detection Guidance

Detecting this vulnerability requires monitoring for abnormal behavior in the Windows WLAN Service. Check for excessive network disconnections or service crashes. Use Event Viewer to review logs for WLAN-related errors under Windows Logs > System. Monitor network traffic for unusual patterns that may indicate a denial-of-service attempt.

Impact Analysis

An unauthorized attacker could disrupt network services by exploiting this flaw, leading to loss of connectivity or network unavailability for affected systems.

Compliance Impact

This vulnerability allows an unauthorized attacker to deny network service, which could disrupt critical operations. For GDPR, this may impact availability of personal data processing systems. For HIPAA, it could disrupt healthcare services dependent on network connectivity.

Mitigation Strategies

Apply the latest security updates from Microsoft to patch the Windows WLAN Service vulnerability. Monitor network traffic for unusual patterns indicating denial of service attempts.

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