{"cve":"CVE-2021-34523","nvd":{"published":"2021-07-14T18:15:12.347","modified":"2026-08-10T19:59:11.883","status":"Analyzed","description":"Microsoft Exchange Server Elevation of Privilege Vulnerability","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N","score":9.0},"cwes":[],"references":["https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34523","http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html","https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34523","https://www.zerodayinitiative.com/advisories/ZDI-21-822/","https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34523"],"products":["microsoft:exchange_server"],"source":"nvd","synced_at":"2026-10-19T21:21:13.713336758+00:00"},"epss":{"cve":"CVE-2021-34523","score":0.9999,"percentile":0.99985,"date":"2026-10-31"},"kev":{"cve":"CVE-2021-34523","date_added":"2021-11-03","due_date":"2021-11-17","vendor":"Microsoft","product":"Exchange Server","known_ransomware":true},"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}