⚡ Exploit-DB.ai CRITICAL
CRITICAL

CVE-2021-26855

Published: March 18, 2026 · Source: National Vulnerability Database (NVD)

⚡ AI Threat Assessment

ProxyLogon SSRF — the entry point for the most significant Exchange mass-exploitation event since EternalBlue. Apply emergency patches immediately. If unpatched during March 2021, assume compromise and run Microsoft MSERT scanner.

📋 Official Description

Microsoft Exchange Server Server-Side Request Forgery (SSRF) vulnerability. Part of the ProxyLogon chain exploited by HAFNIUM and multiple other APT groups.

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