Improper authentication in Microsoft Exchange Server - CVE-2025-59249
Published: October 14, 2025
Vulnerability identifier: #VU117031
CSH Severity: Medium
CVSS v4: 6.4 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:H/SI:H/SA:N]
CVE-ID: CVE-2025-59249
CWE-ID: CWE-287
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to bypass authentication process.
The vulnerability exists due to usage of weak authentication process. A remote user can take over an admin account and use it to compromise mailboxes of other application users.
Affected software
Microsoft Exchange Server
How to mitigate CVE-2025-59249
Install updates from vendor's website.
Microsoft Exchange Server - addressed in versions SE RTM Oct25SU 15.02.2562.029, 2016 CU23 Oct25SU 15.01.2507.061, 2019 CU14 Oct25SU 15.02.1544.036, 2019 CU15 Oct25SU 15.02.1748.039