CVE-2025-55234

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.

Exploit odds

20.8% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-09-09 17:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 09:41 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 20.8% in the next 30 days (EPSS).
• Severity: 8.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-09-09 17:16 UTC

Last modified

2026-06-17 09:41 UTC

Exploit probability

20.8% · EPSS, next 30 days

Weakness

CWE-287 · Improper authentication

Record status

Modified

Affected

• Microsoft Windows 10 1507 < 10.0.10240.21128
• Microsoft Windows 10 1607 < 10.0.14393.8422
• Microsoft Windows 10 1809 < 10.0.17763.7792
• Microsoft Windows 10 21h2 < 10.0.19044.6332
• Microsoft Windows 10 22h2 < 10.0.19045.6332
• Microsoft Windows 11 22h2 < 10.0.22621.5909
• Microsoft Windows 11 23h2 < 10.0.22631.5909
• Microsoft Windows 11 24h2 < 10.0.26100.6508

Attack profile CVSS 3.1 · 8.8

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-55234.md and follow it. Check whether this project is affected by CVE-2025-55234. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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