CVE-2023-21529
Act now ● On CISA KEV — actively exploited used in ransomware
Actively exploited — on the CISA KEV list.
CVSS base
8.8
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS — probability of exploitation (30 days)
62.1%
99.1th percentile
CISA KEV
Listed
Added 2026-04-13 · patch by 2026-04-27
Weakness / dates
CWE-502
Published 2023-02-14 · modified 2026-08-19
Description
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529
- 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-high-tempo-medusa-ransomware-operations/