CVE-2025-59257Network attack vector

Authenticated system crash via improper LSM input validation

Published Oct 14, 2025 · Updated Feb 22, 2026

Improper input-type validation in Microsoft Windows Local Session Manager allows remote authenticated users to crash affected systems. Microsoft identifies the LSM component and validation class but has not disclosed the input, request handler, or erroneous operation. Network access with low privileges is required; successful exploitation interrupts availability without reported data disclosure or modification.

CVSS severity6.5
Medium
EPSS probability1.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input-type validation in Microsoft Windows Local Session Manager allows remote authenticated users to crash affected systems. Microsoft identifies the LSM component and validation class but has not disclosed the input, request handler, or erroneous operation. Network access with low privileges is required; successful exploitation interrupts availability without reported data disclosure or modification.

The record

CVE
CVE-2025-59257
Published
Oct 14, 2025
Updated
Feb 22, 2026
Vendor
Microsoft
Product
Windows Server 2025 (Server Core installation)
Classifications
CWE-1287, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 22, 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 <10.0.26100.6899

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.6899
Microsoft · Windows 11, version 25H2version=10.0.26200.0 <10.0.26200.6899
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.6899
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)version=10.0.25398.0 <10.0.25398.1913
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.6899

Published CVSS scores

6.5Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1287Improper Validation of Specified Type of Input
T1499Endpoint Denial of Service

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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