CVE-2021-42321
CISA KEVPublished November 17, 2021 · Updated April 3, 2026
high
Official Description+
An authenticated attacker could leverage improper validation in cmdlet arguments within Microsoft Exchange and perform remote code execution.
Affected Products
| Vendor | Product |
|---|---|
| Microsoft | Exchange |
Patch Status
Patch by 2021-12-01
Recommended Actions
- Check if your systems use any of the affected products listed above.
- Apply vendor patches immediately if available.
- This vulnerability is in CISA's Known Exploited Vulnerabilities catalog — prioritize remediation.
- Monitor vendor advisories for updates and additional mitigations.
- Review logs for indicators of compromise related to CVE-2021-42321.