Auth bypass in Microsoft Windows 10 1507
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 & SMB Server EPA. Adopt appropriate SMB Server hardening measures.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.201 (97.4th percentile), scored .
Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 97.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.201 · newest: 0.201 · change: 0.000
Affected products
- Microsoft Windows 10 1507
- Microsoft Windows 10 1607
- Microsoft Windows 10 1809
- Microsoft Windows 10 21h2
- Microsoft Windows 10 22h2
- Microsoft Windows 10 Version 1507 — versions 10.0.10240.0
- Microsoft Windows 10 Version 1607 — versions 10.0.14393.0
- Microsoft Windows 10 Version 1809 — versions 10.0.17763.0
- Microsoft Windows 10 Version 21h2 — versions 10.0.19044.0
- Microsoft Windows 10 Version 22h2 — versions 10.0.19045.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2025-55234 (vendor-advisory, patch, Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-55234?
- CVE-2025-55234 is a high-severity vulnerability in Microsoft Windows 10 1507, classified under Improper Authentication. CVSS score: 8.8/10. Published 2025-09-09.
- How severe is CVE-2025-55234?
- High severity. CVSS v3 base score is 8.8 out of 10.
- Is CVE-2025-55234 known to be exploited?
- 7 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.