CVE-2025-55234

Windows SMB Elevation of Privilege Vulnerability

Public exploit available. Not confirmed exploited in the wild yet. A vendor fix is available.

CVSS 3.18.8High EPSS percentile97th20% chance in 30 days CISA KEVNot listedNo confirmed exploitation
Public exploit: 1 source FixVendor fixNo build named by the sources

Published 2025-09-09Updated 2025-10-17Sources: CVE.org, NVD, BDU

NVD CVE.org

What to do

The vendor has published a fix. Version details are below where the sources state them.

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS97th

Public exploit

CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

1 source with a proof of concept or module.

Exploit links, PoCs and Metasploit modules after sign-in

EPSS

20% chance of exploitation activity in the next 30 days, which ranks it in the 97th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

The patch came 140 days before any public exploit.

2026-06-25OpenVAS check added
2026-06-22EPSS band changelow → moderate
2026-03-07Public exploit / PoCsource: github-poc
2025-10-17Patch availablerecord updated
2025-09-09Publishedweakness classified, att&ck mapped

Affected products

Microsoft Corpcommercial · USaka Microsoft, microsoft corporation

And 57 more affected products. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Scored 8.8 by NVD.

How it is reached

Attack Vector NetworkExploitable remotely over the network without any special conditions
Attack Complexity LowNo special conditions — the attack can be reliably reproduced
Privileges Required NoneNo authentication required — anyone can exploit this
User Interaction RequiredA user must click a link, open a file, or perform some action

Scope

Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

Confidentiality HighTotal information disclosure — all data in the component is compromised
Integrity HighTotal loss of integrity — attacker can modify any data in the component
Availability HighTotal denial of service — the component is completely unavailable