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Windows SMB Server relay elevation-of-privilege flaw (CVE-2025-55234)

Vulnerability
First reported
Last updated
Happening score
H score 53
2 unique sources, 2 articles

Summary

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Microsoft patched CVE-2025-55234 in Windows SMB Server, a zero-day elevation-of-privilege flaw that can be abused through relay attacks. The issue was one of two publicly disclosed zero-days fixed in the September 2025 Patch Tuesday release, and successful exploitation could let an attacker trigger privilege escalation on susceptible configurations. Microsoft says admins should use SMB Server Signing and SMB Server EPA, along with auditing, to reduce relay-attack risk.

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Timeline

  1. 10.09.2025 14:14 1 articles · 8mo ago

    Microsoft patches publicly known Windows SMB privilege escalation CVE-2025-55234

    Initial Disclosure

    Microsoft patched CVE-2025-55234, a publicly known Windows SMB privilege-escalation flaw, as part of September 2025 Patch Tuesday alongside 79 other security issues. The update also adds auditing support for SMB client compatibility with SMB Server signing and SMB Server EPA so administrators can assess their environment before enabling hardening measures against relay attacks.

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  2. 09.09.2025 20:43 2 articles · 8mo ago

    Microsoft enables SMB client compatibility auditing for CVE-2025-55234

    Mitigation Patch Update

    Microsoft releases the Windows updates for CVE-2025-55234 and enables support for auditing SMB client compatibility for SMB Server signing and SMB Server EPA on and after September 9, 2025, giving administrators a way to harden susceptible Windows SMB Server configurations against relay attacks while checking for compatibility issues with older devices and implementations.

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  3. 09.09.2025 20:43 1 articles · 8mo ago

    Microsoft discloses CVE-2025-55234 Windows SMB Server relay elevation-of-privilege zero-day

    Initial Disclosure

    Microsoft describes CVE-2025-55234 as a publicly disclosed Windows SMB Server elevation-of-privilege flaw that can be exploited through relay attacks, and says the disclosure has not been attributed to any researcher.

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