Overview
An authenticated attacker could leverage improper validation in cmdlet arguments within Microsoft Exchange and perform remote code execution.
https://nvd.nist.gov/vuln/detail/CVE-2021-42321
Key Details
| Property | Value |
|---|---|
| CVE ID | CVE-2021-42321 |
| Vendor / Product | Microsoft — Exchange |
| NVD Published | 2021-11-10 |
| NVD Last Modified | 2025-10-30 |
| CVSS 3.1 Score | 8.8 |
| CVSS 3.1 Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Severity | HIGH |
| CISA KEV Added | 2021-11-17 |
| CISA KEV Deadline | 2021-12-01 |
| Known Ransomware Use | ⚠️ Yes |
CVSS 3.1 Breakdown
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Required Action
CISA BOD 22-01 Deadline: 2021-12-01.
Apply updates per vendor instructions.
Timeline
| Date | Event |
|---|---|
| 2021-11-17 | Added to CISA Known Exploited Vulnerabilities catalog |
| 2021-12-01 | CISA BOD 22-01 remediation deadline |
References
| Resource | Type |
|---|---|
| NVD — CVE-2021-42321 | Vulnerability Database |
| CISA KEV Catalog Entry | US Government |