Zero-day vulnerability in Microsoft Exchange Server

Input validation error

Vulnerability details

Advisory: SB2021110928 - Remote code execution in Microsoft Exchange Server

Vulnerable component: Microsoft Exchange Server

CVE-ID: CVE-2021-42321

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-20 - Improper input validation


The vulnerability allows a remote user to compromise the affected system.

The vulnerability exists due to insufficient validation of cmdlet arguments. A remote user can run a specially crafted cmdlet and execute arbitrary commands on the system.

Note, the vulnerability is being actively exploited in the wild.

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