
CVE-2021-26855 ProxyLogon: Exchange SSRF, 250,000 Servers
CVE-2021-26855 is a server-side request forgery (SSRF) vulnerability in Microsoft Exchange Server allowing an unauthenticated attacker to bypass authentication and impersonate the Exchange server. Chained with CVE-2021-27065, it achieves pre-authentication RCE. Over 250,000 Exchange servers were compromised within days of public disclosure.
