CVE-2026-96940: CWE-1390: Weak Authentication in Microsoft Microsoft Exchange Server 2016 Cumulative Update 23
Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network.
AI Analysis
Technical Summary
This vulnerability, identified as CWE-1390, exists in Microsoft Exchange Server 2016 Cumulative Update 23. It involves weak authorization controls that permit an authenticated attacker to escalate privileges remotely. The CVSS 3.1 base score is 8.8, indicating high impact on confidentiality, integrity, and availability. The affected versions include multiple builds prior to certain update thresholds in the 15.01 and 15.02 version series. Microsoft has published an official fix to address this issue.
Potential Impact
An authenticated attacker can exploit this vulnerability to elevate their privileges on the affected Microsoft Exchange Server 2016 instances. This can lead to full compromise of the server, impacting confidentiality, integrity, and availability of the system and potentially the broader network environment.
Mitigation Recommendations
Microsoft has released an official fix for this vulnerability. Users should apply the security updates provided by Microsoft for Exchange Server 2016 Cumulative Update 23 to remediate this issue. No additional mitigation steps are indicated beyond applying the official patch.
CVE-2026-96940: CWE-1390: Weak Authentication in Microsoft Microsoft Exchange Server 2016 Cumulative Update 23
Description
Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network.
CVSS v3.1
Score 8.8high
Affected software
Microsoft
Microsoft Exchange Server 2016 Cumulative Update 23
Microsoft
Microsoft Exchange Server 2019 Cumulative Update 14
Microsoft
Microsoft Exchange Server 2019 Cumulative Update 15
Microsoft
Microsoft Exchange Server Subscription Edition RTM
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability, identified as CWE-1390, exists in Microsoft Exchange Server 2016 Cumulative Update 23. It involves weak authorization controls that permit an authenticated attacker to escalate privileges remotely. The CVSS 3.1 base score is 8.8, indicating high impact on confidentiality, integrity, and availability. The affected versions include multiple builds prior to certain update thresholds in the 15.01 and 15.02 version series. Microsoft has published an official fix to address this issue.
Potential Impact
An authenticated attacker can exploit this vulnerability to elevate their privileges on the affected Microsoft Exchange Server 2016 instances. This can lead to full compromise of the server, impacting confidentiality, integrity, and availability of the system and potentially the broader network environment.
Mitigation Recommendations
Microsoft has released an official fix for this vulnerability. Users should apply the security updates provided by Microsoft for Exchange Server 2016 Cumulative Update 23 to remediate this issue. No additional mitigation steps are indicated beyond applying the official patch.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-09-23T20:35:19.927Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96940","vendor":"Microsoft"}]
Threat ID: 6ac00321a43b0b3b89f06a33
Added to database: 10/02/2026, 19:16:49 UTC
Last enriched: 10/02/2026, 19:31:00 UTC
Last updated: 10/02/2026, 20:31:41 UTC
Views: 4
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