#VU109096 Improper Authentication in Microsoft Defender for Identity - CVE-2025-26685

Vulnerability identifier: #VU109096

Vulnerability risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-26685

CWE-ID: CWE-287

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Microsoft Defender for Identity
Client/Desktop applications / Antivirus software/Personal firewalls

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error when processing authentication requests in Microsoft Defender for Identity. A remote attacker on the local network can bypass authentication process and perform spoofing attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Defender for Identity: All versions

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External links
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-26685

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.