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OpenAdvisories
High · 8.8 Known exploited · Ransomware Public exploit CVE-2021-42321 EUVD-2021-29296GHSA-3f87-66x4-f3p7

Microsoft Exchange Server Remote Code Execution Vulnerability

Published Nov 10, 2021 · Updated Aug 19, 2026 · Assigned by microsoft

Vendor: Microsoft Product: Microsoft Exchange Server 2016 Cumulative Update 21 Product: Microsoft Exchange Server 2016 Cumulative Update 22 Product: Microsoft Exchange Server 2019 Cumulative Update 10 Product: Microsoft Exchange Server 2019 Cumulative Update 11

Description

Microsoft Exchange Server Remote Code Execution Vulnerability

Affected products

VendorProductAffectedFixed
Microsoft Microsoft Exchange Server 2016 Cumulative Update 21 15.01.0 – < 15.01.2308.020 15.01.2308.020
Microsoft Microsoft Exchange Server 2016 Cumulative Update 22 15.0.0 – < 15.01.2375.017 15.01.2375.017
Microsoft Microsoft Exchange Server 2019 Cumulative Update 10 15.02.0 – < 15.02.0792.019 15.02.0792.019
Microsoft Microsoft Exchange Server 2019 Cumulative Update 11 15.02.0 – < 15.02.0986.014 15.02.0986.014

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

Metasploit 1 module

GitHub 3 repositories

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

Advisories 1

References