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CVE-2025-55234

CRITICALCVSS 9.8/10EPSS 18.83%

Last modified

CVE-2025-55234 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 18.83% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.8/10

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

EPSS Probability
18.83%

96.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
MicrosoftWindows 10 1507< 10.0.10240.21128—
MicrosoftWindows 10 1607< 10.0.14393.8422—
MicrosoftWindows 10 1809< 10.0.17763.7792—
MicrosoftWindows 10 21h2< 10.0.19044.6332—
MicrosoftWindows 10 22h2< 10.0.19045.6332—
MicrosoftWindows 11 22h2< 10.0.22621.5909—
MicrosoftWindows 11 23h2< 10.0.22631.5909—
MicrosoftWindows 11 24h2< 10.0.26100.6508—
MicrosoftWindows Server 2008All versionsSp2
MicrosoftWindows Server 2008r2Sp1
MicrosoftWindows Server 2012All versions—
MicrosoftWindows Server 2012r2—
MicrosoftWindows Server 2016< 10.0.14393.8422—
MicrosoftWindows Server 2019< 10.0.17763.7792—
MicrosoftWindows Server 2022< 10.0.20348.4106—
MicrosoftWindows Server 2022 23h2< 10.0.25398.1849—
MicrosoftWindows Server 2025< 10.0.26100.6508—

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2025-55234?
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 &amp; SMB Server EPA. Adopt appropriate SMB Server hardening measures.
How severe is CVE-2025-55234?
CVE-2025-55234 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 18.83% probability of exploitation in the next 30 days.
How do I fix CVE-2025-55234?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-55234?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST