CVE-2023-23397: Microsoft Office Outlook Privilege Escalation Vulnerability

Vulnerability summary

CVE-2023-23397 is a critical (CVSS 9.8) Improper Input Validation vulnerability in Microsoft Office. It is known to be exploited: CISA lists it, first on 14-03-2023. EPSS estimates a 97.16% chance of exploitation in the next 30 days, higher than 99.8% of scored vulnerabilities.

Timeline

1. 14-03-2023
   PublishedVulnerability first disclosed.
2. 14-03-2023
   Added to CISA KEVMicrosoft Office Outlook Privilege Escalation Vulnerability
3. 04-04-2023
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

Description

Microsoft Outlook Elevation of Privilege Vulnerability

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
• CWE-294Authentication Bypass by Capture-replayA capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).