What’s Vulnerable › Vulnerabilities

CVE-2020-17143: Microsoft Exchange Server Information Disclosure Vulnerability

• Severity: medium (CVSS 6.5 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 70.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-12-09 · updated 2026-06-17

Description

Microsoft Exchange Server Information Disclosure Vulnerability

Affected products

• Microsoft Exchange Server: 2013-cumulative_update_23, 2016-cumulative_update_17, 2016-cumulative_update_18, 2019-cumulative_update_6, 2019-cumulative_update_7
• Microsoft Exchange Server 2013 Cumulative Update 23: from 15.00.0 before publication — fixed in publication
• Microsoft Exchange Server 2016 Cumulative Update 17: from 15.01.0 before publication — fixed in publication
• Microsoft Exchange Server 2016 Cumulative Update 18: from 15.01.0 before publication — fixed in publication
• Microsoft Exchange Server 2019 Cumulative Update 6: from 15.02.0 before publication — fixed in publication
• Microsoft Exchange Server 2019 Cumulative Update 7: from 15.02.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft Exchange Server 2013 Cumulative Update 23 publication; Microsoft Exchange Server 2016 Cumulative Update 17 publication; Microsoft Exchange Server 2016 Cumulative Update 18 publication; Microsoft Exchange Server 2019 Cumulative Update 6 publication; Microsoft Exchange Server 2019 Cumulative Update 7 publication. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-17143
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-17143

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