CVE-2021-31207: Microsoft Exchange Server Security Feature Bypass

Microsoft Exchange Server Security Feature Bypass Vulnerability. Microsoft Exchange Server contains an unspecified vulnerability that allows for security feature bypass.

• CISA KEV-listed (remediation due 2021-11-17)
• used in ransomware campaigns
• EPSS 99.8% (100.0% percentile)
• CVSS 6.6 medium

Related briefings

• CISA #StopRansomware: Hive Ransomware Claims 1,300+ Victims and $100M in Payments Targeting Healthcare and Critical Infrastructure 2026-02-16

Linked threat actors

• Hive

Browse the CVE database

Read the full analysis on IntelFusions