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Medium · 6.6 Known exploited · Ransomware Public exploit CVE-2021-31207 EUVD-2021-18120GHSA-jcxv-6f65-7hrx

Microsoft Exchange Server Security Feature Bypass Vulnerability

Published May 11, 2021 · Updated Oct 21, 2025 · Assigned by microsoft

Description

Microsoft Exchange Server Security Feature Bypass Vulnerability

Affected products

VendorProductAffectedFixed
Microsoft Microsoft Exchange Server 2013 Cumulative Update 23 15.00.0 – < 15.00.1497.018 15.00.1497.018
Microsoft Microsoft Exchange Server 2019 Cumulative Update 9 15.02.0 – < 15.02.0858.012 15.02.0858.012
Microsoft Microsoft Exchange Server 2016 Cumulative Update 20 15.01.0 – < 15.01.2242.010 15.01.2242.010
Microsoft Microsoft Exchange Server 2016 Cumulative Update 19 15.01.0 – < 15.01.2176.014 15.01.2176.014
Microsoft Microsoft Exchange Server 2019 Cumulative Update 8 15.02.0 – < 15.02.0792.015 15.02.0792.015

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

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

References