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OpenAdvisories
High · 8.8 Exploitation more likely Publicly disclosed Public exploit CVE-2025-55234 EUVD-2025-27294GHSA-9x8h-hfmc-8j5r

Windows SMB Elevation of Privilege Vulnerability

Published Sep 9, 2025 · Updated Feb 26, 2026 · Assigned by microsoft

Vendor: Microsoft Product: Windows 10 Version 1507 Product: Windows 10 Version 1607 Product: Windows 10 Version 1809 Product: Windows 10 Version 21H2 Product: Windows 10 Version 22H2 Product: Windows 11 version 22H2 Product: Windows 11 version 22H3 Product: Windows 11 version 23H2 Product: Windows 11 Version 24H2 Product: Windows Server 2008 R2 Service Pack 1 Product: Windows Server 2008 R2 Service Pack 1 (Server Core installation) Product: Windows Server 2008 Service Pack 2 Product: Windows Server 2008 Service Pack 2 (Server Core installation) Product: Windows Server 2012 Product: Windows Server 2012 (Server Core installation) Product: Windows Server 2012 R2 Product: Windows Server 2012 R2 (Server Core installation) Product: Windows Server 2016 Product: Windows Server 2016 (Server Core installation) Product: Windows Server 2019 Product: Windows Server 2019 (Server Core installation) Product: Windows Server 2022 Product: Windows Server 2022, 23H2 Edition (Server Core installation) Product: Windows Server 2025 Product: Windows Server 2025 (Server Core installation) Platform: Windows

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.

Affected products

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

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 2 repositories

  • mrk336/Patch-the-Path-CVE-2025-55234-Detection-Defense ★ 1 · Sep 15, 2025

    This playbook outlines detection, containment, and remediation strategies for CVE-2025-55234, a critical Windows SMB privilege escalation flaw.

  • mrk336/CVE-2025-55234 ★ 1 · Sep 13, 2025

    This vulnerability allows attackers to perform relay attacks against the SMB (Server Message Block) protocol. If successful, it can lead to Elevation of Privilege (EoP) essentially allowing unauthori…

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

Advisories 3

References