CVE-2025-29955

Local denial of service

Published May 13, 2025 · Updated Feb 13, 2026

Improper input validation in Microsoft Windows Hyper-V allows local users to cause a denial of service on affected x64 hosts. Microsoft has not disclosed the input locus, rejected value, or resulting failure mode beyond classifying the flaw as improper input validation. Exploitation requires local access but no privileges or user interaction, and the published impact is limited to availability.

CVSS severity6.2
Medium
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Microsoft Windows Hyper-V allows local users to cause a denial of service on affected x64 hosts. Microsoft has not disclosed the input locus, rejected value, or resulting failure mode beyond classifying the flaw as improper input validation. Exploitation requires local access but no privileges or user interaction, and the published impact is limited to availability.

The record

CVE
CVE-2025-29955
Published
May 13, 2025
Updated
Feb 13, 2026
Vendor
Microsoft
Product
Windows Server 2025 (Server Core installation)
Classifications
CWE-20, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 13, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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 <10.0.26100.4061

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.4061
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.4061
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)version=10.0.25398.0 <10.0.25398.1611
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.4061

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.2Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Application or System Exploitation

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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