6.6
Medium
Exploited
· ransomware
ProxyShell
CVE-2021-31207 Microsoft Exchange Server Security Feature Bypass Vulnerability
Active exploitation observed
· CISA KEV catalogue
Required action
Apply updates per vendor instructions.
Ransomware campaigns
Known to be used
Weakness
CWE-20, CWE-434
Description
Microsoft Exchange Server Security Feature Bypass Vulnerability
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Microsoft Exchange Server 2013 Cumulative Update 23 15.00 | 15.00.0 → < 15.00.1497.018 | 15.00.1497.018 |
| Microsoft Exchange Server 2019 Cumulative Update 9 15.02 | 15.02.0 → < 15.02.0858.012 | 15.02.0858.012 |
| Microsoft Exchange Server 2016 Cumulative Update 20 15.01 | 15.01.0 → < 15.01.2242.010 | 15.01.2242.010 |
| Microsoft Exchange Server 2016 Cumulative Update 19 15.01 | 15.01.0 → < 15.01.2176.014 | 15.01.2176.014 |
| Microsoft Exchange Server 2019 Cumulative Update 8 15.02 | 15.02.0 → < 15.02.0792.015 | 15.02.0792.015 |
References
- portal.msrc.microsoft.com portal.msrc.microsoft.com
- www.zerodayinitiative.com www.zerodayinitiative.com
- packetstormsecurity.com packetstormsecurity.com
Timeline
- Published
- Added to the KEV catalogue
- Last modified
Other CVEs of Microsoft Exchange Server 2013 Cumulative Update 23
The 51 CVEs of Microsoft Exchange Server 2013 Cumulative Update 23 →
CVE-2023-21529
Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability
8.8
High
CVE-2023-21707
Microsoft Exchange Server Remote Code Execution Vulnerability
8.8
High
CVE-2023-21706
Microsoft Exchange Server Remote Code Execution Vulnerability
8.8
High
CVE-2023-21762
Microsoft Exchange Server Spoofing Vulnerability
8.0
High