CVE-2021-31207
Published: November 3, 2021
Official Description
Microsoft Exchange Server contains an unspecified vulnerability that allows for security feature bypass.
CISA KEV Advisory
Microsoft Exchange Server Security Feature Bypass Vulnerability
Microsoft Exchange Server contains an unspecified vulnerability that allows for security feature bypass.
Apply updates per vendor instructions.
Risk Analysis
Microsoft Exchange Server is affected by an unspecified vulnerability that allows for security feature bypass. The high EPSS score of 0.93908 indicates a very high likelihood of exploitation, and its presence in CISA's KEV confirms active exploitation.
This vulnerability is actively being exploited in the wild. It is remotely exploitable.
Apply the latest security updates and patches for Microsoft Exchange Server to address this security feature bypass vulnerability.
Technical Analysis
CVE-2021-31207 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-31207 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (1)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-31207 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1