Microsoft · Office
CVE-2023-23397
Microsoft Outlook Elevation of Privilege Vulnerability
Exploited in attacks
Critical 9.8 Attack chance: 97%
What it is
Microsoft Outlook Elevation of Privilege Vulnerability
CISA: Microsoft Office Outlook contains a privilege escalation vulnerability that allows for a NTLM Relay attack against another service to authenticate as the user.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: April 4, 2023
More exploited flaws from Microsoft
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Apr 14, 2026 | Remote Code Execution | Office | High 8.8 | 43% |
| Feb 10, 2026 | Word Reliance on Untrusted Inputs in a Security Decision | Office | High 7.8 | 1.6% |
| Jan 26, 2026 | Security Feature Bypass | Office | High 7.8 | 71% |
| Jan 7, 2026 | PowerPoint Code Injection | Office | High 8.8 | 67% |
| Aug 12, 2025 | Excel Remote Code Execution | Office | High 8.8 | 43% |
| Feb 14, 2023 | Publisher Security Feature Bypass | Office | High 7.3 | 12% |
| Jun 8, 2022 | Object Record Corruption | Office | High 7.8 | 53% |
| Jun 8, 2022 | Buffer Overflow | Office | High 7.8 | 60% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.