CVE-2023-21529

Description

Microsoft Exchange Server Remote Code Execution Vulnerability

Scoring

• CVSS: 8.8 (HIGH, 3.1)
• EPSS exploitation probability: Not yet available
• EPSS percentile: Not yet available

CISA KEV status

• Added to KEV: 2026-04-13
• Remediation due date: 2026-04-27
• Known ransomware campaign use: Known

Weakness types (CWE)

• CWE-502

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/

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