CVE-2025-55234 Windows SMB Elevation of Privilege Vulnerability
Attackers can exploit SMB relay attacks to elevate privileges if SMB signing and Extended Protection for Authentication are not enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2025-55234?
CVE-2025-55234 is a high-severity authentication bypass vulnerability in Microsoft Windows 10 1507, published on 9 Sep 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-287
Which versions are affected by CVE-2025-55234?
It affects 15 products.
Products include Microsoft Windows 10 1507, Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 22h2 and 9 more.
How do I fix CVE-2025-55234?
No fix has been published for CVE-2025-55234 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2025-55234 being exploited?
There is no known exploitation of CVE-2025-55234 in the wild and no public exploit code.
Public exploit code: 2 proofs of concept on GitHub.
Other vulnerabilities in Microsoft Windows 10 1507
- CVE-2017-8543 Microsoft Windows Search Remote Code Execution
- CVE-2025-33053 Microsoft Windows External Control of File Name or Path
- CVE-2025-33073 Microsoft Windows SMB Client Improper Access Control
- CVE-2024-49039 Microsoft Windows Task Scheduler Privilege Escalation
- CVE-2024-43461 Microsoft Windows MSHTML Platform Spoofing
Sources
Also known as GHSA-9x8h-hfmc-8j5r.