Live › vulnerability › CVE-2021-31207
Go to dashboardMicrosoft Exchange Server has a security feature bypass flaw that CISA lists as exploited in the wild, and ransomware use is tagged. The sources do not describe exactly what the bypass grants, so the worst case below is inferred from the ProxyLogon-era chain it belongs to, not stated.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 19:11 UTC, 3h before NVD. All times on this page are UTC.
Apply updates per vendor instructions.
| Product | Ecosystem | Affected | Fixed in |
|---|---|---|---|
| Microsoft Exchange Server | vendor | – | – |
Check the installed Exchange build version against Microsoft's security update list for CVE-2021-31207 (sources do not give a command).
Apply the Microsoft Exchange Server security update for CVE-2021-31207 per vendor instructions (CISA required action); exact fixed build unknown from sources.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
Microsoft Exchange Server contains an unspecified vulnerability that allows for security feature bypass.
CISA required action: Apply updates per vendor instructions.
This page as .md · .json · in your agent: get_signal("CVE-2021-31207")
CISA KEV catalog, Creative Commons 0 · EPSS scores by FIRST, used with attribution · NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.