CVE-2025-55234 [High] | Authentication Bypass in Windows 10 1507

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.97%	18.83%	+17.86%
2	2026-06-05	0.41%	0.97%	+0.57%
3	2026-05-26	—	0.41%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.97%

18.83%

+17.86%

2026-06-05

0.41%

0.97%

+0.57%

2026-05-26

—

0.41%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.8	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	5.9	[email protected]
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.8

3.1

HIGH

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

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

5.9

[email protected]

9.8

3.1

CRITICAL

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

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.9

[email protected]

Affected software / configurations for CVE-2025-55234

Vendor	Product	Version	Raw CPE
microsoft	windows_10_1507	< 10.0.10240.21128	cpe:2.3:o:microsoft:windows_10_1507:::::::x64:*
microsoft	windows_10_1507	< 10.0.10240.21128	cpe:2.3:o:microsoft:windows_10_1507:::::::x86:*
microsoft	windows_10_1607	< 10.0.14393.8422	cpe:2.3:o:microsoft:windows_10_1607:::::::x64:*
microsoft	windows_10_1607	< 10.0.14393.8422	cpe:2.3:o:microsoft:windows_10_1607:::::::x86:*
microsoft	windows_10_1809	< 10.0.17763.7792	cpe:2.3:o:microsoft:windows_10_1809:::::::x64:*
microsoft	windows_10_1809	< 10.0.17763.7792	cpe:2.3:o:microsoft:windows_10_1809:::::::x86:*
microsoft	windows_10_21h2	< 10.0.19044.6332	cpe:2.3:o:microsoft:windows_10_21h2::::::::
microsoft	windows_10_22h2	< 10.0.19045.6332	cpe:2.3:o:microsoft:windows_10_22h2::::::::
microsoft	windows_11_22h2	< 10.0.22621.5909	cpe:2.3:o:microsoft:windows_11_22h2::::::::
microsoft	windows_11_23h2	< 10.0.22631.5909	cpe:2.3:o:microsoft:windows_11_23h2::::::::
microsoft	windows_11_24h2	< 10.0.26100.6508	cpe:2.3:o:microsoft:windows_11_24h2::::::::
microsoft	windows_server_2008	—	cpe:2.3:o:microsoft:windows_server_2008:-:sp2:::::x64:*
microsoft	windows_server_2008	—	cpe:2.3:o:microsoft:windows_server_2008:-:sp2:::::x86:*
microsoft	windows_server_2008	r2	cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:::::x64:*
microsoft	windows_server_2012	—	cpe:2.3:o:microsoft:windows_server_2012:-:::::::*
microsoft	windows_server_2012	r2	cpe:2.3:o:microsoft:windows_server_2012:r2:::::::*
microsoft	windows_server_2016	< 10.0.14393.8422	cpe:2.3:o:microsoft:windows_server_2016::::::::
microsoft	windows_server_2019	< 10.0.17763.7792	cpe:2.3:o:microsoft:windows_server_2019::::::::
microsoft	windows_server_2022	< 10.0.20348.4106	cpe:2.3:o:microsoft:windows_server_2022::::::::
microsoft	windows_server_2022_23h2	< 10.0.25398.1849	cpe:2.3:o:microsoft:windows_server_2022_23h2::::::::
microsoft	windows_server_2025	< 10.0.26100.6508	cpe:2.3:o:microsoft:windows_server_2025::::::::

References for CVE-2025-55234

URL	Tags
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-55234	Vendor Advisory
https://www.vicarius.io/vsociety/posts/cve-2025-55234-detection-script-smb-server-vulnerability-affecting-microsoft-systems
https://www.vicarius.io/vsociety/posts/cve-2025-55234-mitigation-script-smb-server-vulnerability-affecting-microsoft-systems

URL

CVE-2025-55234 | Windows SMB Elevation of Privilege Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2025-55234

Common vulnerability scoring system (CVSS) metrics for CVE-2025-55234

Weakness enumeration for CVE-2025-55234

Affected software / configurations for CVE-2025-55234

References for CVE-2025-55234