⚡ Exploit-DB.ai HIGH
HIGH

CVE-2021-26857

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

⚡ AI Threat Assessment

ProxyLogon SYSTEM RCE via Exchange Unified Messaging deserialization — chained with CVE-2021-26855 SSRF for full unauthenticated compromise. Apply March 2021 emergency patches and run Microsoft MSERT to detect webshells already deployed.

📋 Official Description

Microsoft Exchange Server remote code execution vulnerability due to insecure deserialization used by the Unified Messaging service. Part of the ProxyLogon family.

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