CVE-2021-31207

Known Exploited Public Exploit
Microsoft Exchange Server Security Feature Bypass Vulnerability

Description

Microsoft Exchange Server Security Feature Bypass Vulnerability

Category

6.6
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 94.03% Top 5%
KEV Since 
Vendor Advisory microsoft.com
Affected: Microsoft Microsoft Exchange Server 2013 Cumulative Update 23
Affected: Microsoft Microsoft Exchange Server 2019 Cumulative Update 9
Affected: Microsoft Microsoft Exchange Server 2016 Cumulative Update 20
Affected: Microsoft Microsoft Exchange Server 2016 Cumulative Update 19
Affected: Microsoft Microsoft Exchange Server 2019 Cumulative Update 8
Published at:
Updated at:

References

Link Tags
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207 patch vendor advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-819/ vdb entry third party advisory
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html exploit vdb entry third party advisory

Frequently Asked Questions

What is the severity of CVE-2021-31207?
CVE-2021-31207 has been scored as a medium severity vulnerability.
How to fix CVE-2021-31207?
To fix CVE-2021-31207, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-31207 being actively exploited in the wild?
It is confirmed that CVE-2021-31207 is actively exploited. Be extra cautious if you are using vulnerable components. According to its EPSS score, there is a ~94% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-31207?
CVE-2021-31207 affects Microsoft Microsoft Exchange Server 2013 Cumulative Update 23, Microsoft Microsoft Exchange Server 2019 Cumulative Update 9, Microsoft Microsoft Exchange Server 2016 Cumulative Update 20, Microsoft Microsoft Exchange Server 2016 Cumulative Update 19, Microsoft Microsoft Exchange Server 2019 Cumulative Update 8.
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