Actively exploited · CISA KEV · NVD published 2021-03-03
Actively exploitedCVE-2021-26855
Microsoft Exchange Server Remote Code Execution Vulnerability
- First PoC
- 1033 days →Metasploit
- 1014 days →First cited attacker
Signals
- Exploited in the wild
- Yesadded 2021-11-03 · due 2022-05-03 · known ransomware use. An observation, not a forecast.
- EPSS · 30-day forecast
- 100.0%Chance of exploitation in the next 30 days, 100th percentile of all CVEs. A forecast; KEV outranks it.
- CVSS · NVD · CRITICAL
- 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Internet exposure
- not stated by sourcesNo exposure census on this CVE's dispatches.
Exploits
8 known · links onlyMetasploit3
This module exploit a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authentication and impersonating as the admin (CVE-2021-26855). By taking advantage of this vulnerability, it is possible to dump all mailboxes (emails, attachments, contacts, ...). This vulnerability affects (Exchange 2013 Versions < 15.00.1497.012, Exchange 2016 CU18 < 15.01.2106.013, Exchange 2016 CU19 < 15.01.2176.009,
ruby · seen 2026-10-18
This module exploit a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authentication, impersonating as the admin (CVE-2021-26855) and write arbitrary file (CVE-2021-27065) to get the RCE (Remote Code Execution). By taking advantage of this vulnerability, you can execute arbitrary commands on the remote Microsoft Exchange Server. This vulnerability affects (Exchange 2013 Versions < 15.00.1497.012,
ruby · seen 2026-10-18
This module scan for a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authentication and impersonating as the admin (CVE-2021-26855). By chaining this bug with another post-auth arbitrary-file-write vulnerability to get code execution (CVE-2021-27065). As a result, an unauthenticated attacker can execute arbitrary commands on Microsoft Exchange Server. This vulnerability affects (Exchange 2
ruby · seen 2026-10-18
Exploit-DB4
created 2021-03-11
created 2021-03-14
created 2021-05-18
created 2021-05-21
Nuclei1
This vulnerability is part of an attack chain that could allow remote code execution on Microsoft Exchange Server. The initial attack requires the ability to make an untrusted connection to Exchange server port 443. Other portions of the chain can be triggered if an attacker already has access or can convince an administrator to open a malicious file. Be aware his CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065, and CVE-2021-27078.
yaml · seen 2026-10-18
On the wire
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