# Microsoft Office Outlook: Outlook Improper Input Validation Vulnerability · pwn.watch

> Microsoft Outlook contains an improper input validation vulnerability that allows for remote code execution. Successful exploitation of this vulnerability would allow an attacker to bypass the Office Protected View and open in editing mode rather than protected mode. Added to CISA KEV on 2025-02-06.

Page: https://pwn.watch/i/microsoft-office-outlook-cve-2024-21413 · generated 2026-10-22T22:00:08.805Z

## Status
- Severity: critical · status: closed · patch: patched
- Product: Microsoft Office Outlook
- Started: 2025-02-06 · closed: 2025-02-06
- CVEs: CVE-2024-21413
- Affected: See vendor advisory / CISA notes (versions not always listed in KEV feed)
- Fixed in: See vendor advisory linked in sources

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/microsoft-office-outlook-cve-2024-21413/feed.xml
- JSON Feed: https://pwn.watch/i/microsoft-office-outlook-cve-2024-21413/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/microsoft-office-outlook-cve-2024-21413.json
- This file: https://pwn.watch/i/microsoft-office-outlook-cve-2024-21413/llms.txt

## Updates (newest first)
- 2025-02-06: CISA added CVE-2024-21413 to the KEV catalog (due 2025-02-27).

## Fix brief
# Security brief: Microsoft Office Outlook: Outlook Improper Input Validation Vulnerability

Source: https://pwn.watch/i/microsoft-office-outlook-cve-2024-21413 · status: closed (closed Feb 6, 2025) · severity: critical · updated Feb 6, 2025

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## What it is
Microsoft Outlook contains an improper input validation vulnerability that allows for remote code execution. Successful exploitation of this vulnerability would allow an attacker to bypass the Office Protected View and open in editing mode rather than protected mode. Added to CISA KEV on 2025-02-06.

Severity detail: CVSS 9.8 (CNA, v3.1); actively exploited (CISA KEV)

- Product: Microsoft Office Outlook
- CVE / advisory ids: CVE-2024-21413

## Affected versions
- See vendor advisory / CISA notes (versions not always listed in KEV feed)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- See vendor advisory linked in sources

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Latest updates
- Feb 6, 2025: CISA added CVE-2024-21413 to the KEV catalog (due 2025-02-27).

## Advisories
- [Microsoft advisory: Microsoft Office Outlook](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21413) (Microsoft)
- [NVD: CVE-2024-21413](https://nvd.nist.gov/vuln/detail/CVE-2024-21413) (NVD)
- [CISA Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog) (CISA)

## Caveats
Derived from CISA KEV JSON feed catalogVersion 2026.10.21. CVSS from the CVE record (cvelistV5). Exact affected/fixed version strings are not always in the KEV record; verify against the vendor advisory URL. startedAt uses dateAdded (exploitation may have begun earlier; many entries are older CVEs newly confirmed as exploited in 2025).

---
Machine-readable: https://pwn.watch/i/microsoft-office-outlook-cve-2024-21413.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.