CVE-2021-31207
MEDIUM severity · CVSS 6.6 · Unrestricted file upload · actively exploited (CISA KEV)
6.6CVSS MEDIUM ● exploited ⚠ ransomware
🔴 Actively exploited in the wild (CISA Known Exploited Vulnerabilities).
⚠ Known use in ransomware campaigns. Added to KEV 2021-11-03. US federal agencies must patch by 2021-11-17.
Summary
Microsoft Exchange Server Security Feature Bypass Vulnerability
Impact & exploitability
Attack vectorNetwork
Attack complexityHigh
Privileges requiredHigh
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)94%
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Affected products we track (1)
Recommendation
This vulnerability is being actively exploited in the wild — patch affected products urgently. Open any affected product above for its exact safe version.
Official patch: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207 ↗
Additional information
- NVD record
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207Patch
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207Patch
- https://www.zerodayinitiative.com/advisories/ZDI-21-819/Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-819/Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31207
- http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.htmlAdvisory
- http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.htmlAdvisory