CVE-2023-21529

high

Description

Microsoft Exchange Server Remote Code Execution Vulnerability

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529

https://www.securityweek.com/organizations-warned-of-exploited-windows-adobe-acrobat-vulnerabilities/

https://thehackernews.com/2026/04/cisa-adds-6-known-exploited-flaws-in.html

https://securityaffairs.com/190775/security/u-s-cisa-adds-adobe-fortinet-microsoft-windows-microsoft-exchange-server-and-microsoft-windows-flaws-to-its-known-exploited-vulnerabilities-catalog.html

https://www.theregister.com/2026/04/13/ransomware_gang_other_crims_attacking/

https://www.cisa.gov/news-events/alerts/2026/04/13/cisa-adds-seven-known-exploited-vulnerabilities-catalog

https://www.darkreading.com/threat-intelligence/storm-1175-medusa-ransomware-high-velocity

https://thehackernews.com/2026/04/china-linked-storm-1175-exploits-zero.html

https://securityaffairs.com/190440/cyber-crime/fast-moving-storm-1175-uses-new-exploits-to-breach-networks-and-drop-medusa.html

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/

https://www.bleepingcomputer.com/news/security/microsoft-links-medusa-ransomware-affiliate-to-zero-day-attacks/

https://www.zerodayinitiative.com/blog/2024/9/11/exploiting-exchange-powershell-after-proxynotshell-part-2-approvedapplicationcollection

https://www.zerodayinitiative.com/blog/2024/9/4/exploiting-exchange-powershell-after-proxynotshell-part-1-multivaluedproperty

https://www.tenable.com/blog/microsofts-february-2023-patch-tuesday-addresses-75-cves-cve-2023-23376

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21529

Details

Source: Mitre, NVD

Published: 2023-02-14

Updated: 2026-04-14

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 9

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 8.8

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Severity: High

EPSS

EPSS: 0.28939