Patchfirst
Class familyMicrosoft · Exchange Server

Microsoft Exchange Server authentication bypass flaws, 2020–2026

5 Exchange Server CVEs with CWE-287 weaknesses, 11 Feb 2020 to 24 Jul 2026. 4 are in .

CVEs by year

Published each year. Select a CVE to open it.

Grouped by product and weakness type (CWE); not proven to share a root cause.

In CISA KEVNot in KEV

20201 CVE, 1 in KEV

20212 CVEs, 2 in KEV

20241 CVE, 1 in KEV

20261 CVE

CVEs in this family

Table view of the years above
CVEPublishedTitleLinked fromPriority
CVE-2020-0688KEV 11 Feb 2020 Microsoft Exchange Server Validation Key Remote Code Execution Vulnerability Grouped by weakness 86.9
CVE-2021-33766KEV 14 Jul 2021 Microsoft Exchange Server Information Disclosure Grouped by weakness 68.1
CVE-2021-34523KEV 14 Jul 2021 Microsoft Exchange Server Privilege Escalation Vulnerability Grouped by weakness 89.3
CVE-2024-21410KEV 13 Feb 2024 Microsoft Exchange Server Privilege Escalation Vulnerability Grouped by weakness 64.1
CVE-2026-56191 24 Jul 2026 Microsoft Exchange Online Tampering Vulnerability Grouped by weakness 18.9
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