CVE-2021-31209: Microsoft Exchange Server Spoofing Vulnerability

Overview

Severity

Medium (CVSS 6.5)

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N/E:U/RL:O/RC:C

Category

Spoofing

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2021-May

Released

2021-05-11

Last Updated

2021-05-13

EPSS Score

0.65% (percentile: 70.8%)

FAQ

Was this vulnerability found in the 2021 Pwn2Own contest? Yes, this was one of the Exchange Server vulnerabilities found in the 2021 Pwn2Own contest.

Affected Products (5)

Exchange Server

• Microsoft Exchange Server 2019 Cumulative Update 9
• Microsoft Exchange Server 2016 Cumulative Update 20
• Microsoft Exchange Server 2013 Cumulative Update 23
• Microsoft Exchange Server 2016 Cumulative Update 19
• Microsoft Exchange Server 2019 Cumulative Update 8

Security Updates (5)

• 5003435
• 5003435
• 5003435
• 5003435
• 5003435

Acknowledgments

Steven Seeley (mr_me) of Source Incite working with Trend Micro Zero Day Initiative, Anonymous working with <a href="https://www.zerodayinitiative.com/">Trend Micro Zero Day Initiative</a>

Revision History

• 2021-05-11: Information published.
• 2021-05-13: Added acknowledgements. This is an informational change only.