CVEvulnerability
CVE-2021-42321
CISA Known Exploited Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability — Microsoft Exchange
An authenticated attacker could leverage improper validation in cmdlet arguments within Microsoft Exchange and perform remote code execution.
- Added to KEV
- 2021-11-17
- Remediation due
- 2021-12-01
- Ransomware use
- Known
- Required action
- Apply updates per vendor instructions.
- Notes
- https://nvd.nist.gov/vuln/detail/CVE-2021-42321
- Status
- Analyzed
- Published
- 2021-11-10
- Last modified
- 2026-08-19
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 8.8 HIGH — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CVSS 3.1 ([email protected])
- 8.8 HIGH — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CVSS 2.0 ([email protected])
- 6.5 MEDIUM — AV:N/AC:L/Au:S/C:P/I:P/A:P
Description
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected configurations
• microsoft exchange server 2016
• microsoft exchange server 2019
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42321 Patch, Vendor Advisory
- http://packetstormsecurity.com/files/166153/Microsoft-Exchange-Server-Remote-Code-Execution.html Exploit, Third Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/168131/Microsoft-Exchange-Server-ChainedSerializationBinder-Remote-Code-Execution.html Exploit, Third Party Advisory, VDB Entry
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42321 Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42321 US Government Resource