CVE-2023-21529

Microsoft Exchange Server Remote Code Execution Vulnerability

Score

CVSS 3.1 8.8 High

Status

Analyzed - secure@microsoft.com

Published

2023-02-14

Last modified

2026-08-19

Known exploited (CISA KEV)

since 2026-04-13, action due 2026-04-27: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Weaknesses

CWE-502

Affected products

• Exchange Server (Microsoft)

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21529
• https://www.microsoft.com/en-us/security/blog/2026/04/06/storm-1175-focuses-gaze-on-vulnerable-web-facing-assets-in-hig…