CVE-2026-21527

Microsoft Exchange Server Spoofing Vulnerability

CVE-2026-21527 is fixed in 4 products on 1 platform, first by KB5074995, released February 10, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine

CVSS

6.5

Important

Exploitation

None reported

Exploitation Less Likely

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0814

94th percentile

<p>User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.</p>

Where it's fixed

Product	Fix	Released
Microsoft
Microsoft Exchange Server 2016 Cumulative Update 23	KB5074995	Feb 10, 2026
Microsoft Exchange Server 2019 Cumulative Update 14	KB5074994	Feb 10, 2026
Microsoft Exchange Server 2019 Cumulative Update 15	KB5074993	Feb 10, 2026
Microsoft Exchange Server Subscription Edition RTM	KB5074992	Feb 10, 2026

Details

Published
February 10, 2026
Weakness
User Interface (UI) Misrepresentation of Critical Information
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21527

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