CVE-2021-28481: Microsoft Exchange Server Remote Code Execution Vulnerability

Overview

Severity

Critical (CVSS 9.8)

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Category

Remote Code Execution

Exploit Status

Not Exploited

Exploitation Likelihood

More Likely

Patch Tuesday

2021-Apr

Released

2021-04-13

EPSS Score

38.01% (percentile: 97.2%)

FAQ

Where can I find more information about protecting myself from this vulnerability? Please see the MSRC Blog Post April 2021 Update Tuesday packages now available for more information.

Detection & Weaponization (1 sources)

Maturity: Exploit

• Nuclei templates: Microsoft Exchange - Pre-Auth SSRF / ACL Bypass (ProxyNotFound)

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)

• 5001779
• 5001779
• 5001779
• 5001779
• 5001779

Acknowledgments

National Security Agency, Microsoft Security Team

Revision History

• 2021-04-13: Information published.