CVE-2025-21343Network attack vector

Unauthenticated remote disclosure of sensitive information

Published Jan 14, 2025 · Updated Jun 9, 2026

Information disclosure in Microsoft Windows 11 Web Threat Defense User Service allows remote attackers to read sensitive data over a network. Microsoft identifies improper privilege management but has not published the affected operation, request path, or data exposed by the service. No authentication or user interaction is required; the documented impact is limited to confidentiality.

CVSS severity7.5
High
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Microsoft Windows 11 Web Threat Defense User Service allows remote attackers to read sensitive data over a network. Microsoft identifies improper privilege management but has not published the affected operation, request path, or data exposed by the service. No authentication or user interaction is required; the documented impact is limited to confidentiality.

The record

CVE
CVE-2025-21343
Published
Jan 14, 2025
Updated
Jun 9, 2026
Vendor
Microsoft
Product
Windows 11, version 24H2
Classifications
CWE-269
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.26100.0 <10.0.26100.2894

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.2894
Microsoft · Windows 11 Version 22H3version=10.0.22631.0 <10.0.22631.4751
Microsoft · Windows 11 Version 23H2version=10.0.22631.0 <10.0.22631.4751
Microsoft · Windows 11, version 22H2version=10.0.22621.0 <10.0.22621.4751

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-269Improper Privilege Management

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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