CVE-2025-25006: Microsoft Exchange Server Spoofing Vulnerability

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-08-12 · updated 2026-06-17
Weakness: CWE-167

Description

Improper handling of additional special element in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.

Affected products

Microsoft Exchange Server: 2016-cumulative_update_1, 2016-cumulative_update_10, 2016-cumulative_update_11, 2016-cumulative_update_12, 2016-cumulative_update_13, 2016-cumulative_update_14 (+28); 2016, 2019
Microsoft Exchange Server Subscription Edition: before 15.02.2562.020 — fixed in 15.02.2562.020
Microsoft Exchange Server 2016 Cumulative Update 23: from 15.01.0.0 before 15.01.2507.058 — fixed in 15.01.2507.058
Microsoft Exchange Server 2019 Cumulative Update 14: from 15.02.0.0 before 15.02.1544.033 — fixed in 15.02.1544.033
Microsoft Exchange Server 2019 Cumulative Update 15: from 15.02.0.0 before 15.02.1748.036 — fixed in 15.02.1748.036
Microsoft Exchange Server Subscription Edition RTM: from 15.02.0.0 before 15.02.2562.020 — fixed in 15.02.2562.020

How to fix

Upgrade to a fixed version: Microsoft Exchange Server Subscription Edition 15.02.2562.020; Microsoft Exchange Server 2016 Cumulative Update 23 15.01.2507.058; Microsoft Exchange Server 2019 Cumulative Update 14 15.02.1544.033; Microsoft Exchange Server 2019 Cumulative Update 15 15.02.1748.036; Microsoft Exchange Server Subscription Edition RTM 15.02.2562.020. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-25006

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