CVSS 3.1
8.8 highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVE-2023-21529
High (8.8) in Microsoft Exchange Server. In CISA KEV since 2026-04-13, with known ransomware use. EPSS 59% chance of exploitation in the next 30 days.
Microsoft Exchange Server Remote Code Execution Vulnerability
Severity
- EPSS
- 59% chance of exploitation in the next 30 days; higher than 99% of CVEs (scores of 2026-10-31)
- CISA KEV
- listed 2026-04-13, due 2026-04-27, known ransomware use
- CWE
- CWE-502
- Published
- Modified
- Record from
- the NVD, synced
Affected
- microsoft:exchange_server
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/