CVE-2021-31207 KEV
6.6
MEDIUM · CVSS 3.1 · EPSS 99.8% (pctl 100)
Patch first
On CISA KEV — known exploited in the wild, due 2021-11-17.
Description
Microsoft Exchange Server Security Feature Bypass Vulnerability
Scoring
| CVSS | 6.6 (MEDIUM, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 99.78% — more likely to be exploited than 100% of all CVEs |
| Weakness | CWE-434 |
| On CISA KEV | yes — remediate by 2021-11-17 |
| Public exploit | none known |
| Published | 2021-05-11 |
| Last modified | 2026-06-17 |
CISA KEV
| Name | Microsoft Exchange Server Security Feature Bypass Vulnerability |
|---|---|
| Added | 2021-11-03 |
| Due | 2021-11-17 |
| Vendor / product | Microsoft / Exchange Server |
| Ransomware use | known |
Affected (1)
| Vendor | Product |
|---|---|
| microsoft | exchange server |
References
- http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207
- https://www.zerodayinitiative.com/advisories/ZDI-21-819/
- http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207
- https://www.zerodayinitiative.com/advisories/ZDI-21-819/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31207
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