CVE-2021-26855
Microsoft Exchange Server Remote Code Execution Vulnerability
- Published
- Mar 2, 2021
- Updated
- Aug 12, 2026
- Assigning CNA
- microsoft
- Evidence observed
- Mar 11, 2021
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HHigh · next 30 days
- Percentile
- 100.0%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
CISA Known Exploited
This CVE appears in the CISA Known Exploited Vulnerabilities catalog.
Summary
Microsoft Exchange Server Remote Code Execution Vulnerability
Sources
46- CVE-2021-26855-Exchange-RCEExploit
Microsoft Exchange Proxylogon Exploit Chain EXP分析
- proxylogscanScanner
A fast tool to mass scan for a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authentication and impersonating as the admin (CVE-2021-26855).
- ExchangeSSRFtoRCEExploitExploit
Exploit chain for CVE-2021-26855 (SSRF) and CVE-2021-27065 (RCE) targeting Microsoft Exchange servers, enabling remote code execution via ProxyLogon vulnerability.
Responsible use
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