CVE-2024-21413

Microsoft Outlook Improper Input Validation Vulnerability

9.8

CVSS

94.7%

EPSS (exploit prob.)

99.9%

EPSS percentile

Yes

Actively exploited

Ransomware use

2025-02-06

Added

→ 0.0 pts

30-day EPSS trend

MITRE ATT&CK techniques

How this vulnerability maps to adversary behaviour, from the Center for Threat-Informed Defense's public CVE→ATT&CK mappings. Use it to check whether your detections already cover the technique.

Technique	Name	Relationship
T1566.002	Spearphishing Link	exploitation technique
T1059	Command and Scripting Interpreter	primary impact

Summary

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.

Affected software

Vendor: Microsoft · Product: Office Outlook

Weakness types (CWE):

What to do

This vulnerability appears in CISA's Known Exploited Vulnerabilities catalog, meaning it is being exploited in the wild. Prioritize patching affected systems and verify exposure across your estate.

Related vulnerabilities in Microsoft

CVE	Name	EPSS	Exploited
CVE-2021-34473	Microsoft Exchange Server Remote Code Execution Vulnerability	100.0%	Yes
CVE-2019-0708	Microsoft Remote Desktop Services Remote Code Execution Vulnerability	100.0%	Yes
CVE-2015-1635	Microsoft HTTP.sys Remote Code Execution Vulnerability	100.0%	Yes
CVE-2025-53770	Microsoft SharePoint Deserialization of Untrusted Data Vulnerability	100.0%	Yes
CVE-2021-26855	Microsoft Exchange Server Remote Code Execution Vulnerability	100.0%	Yes
CVE-2025-49704	Microsoft SharePoint Code Injection Vulnerability	100.0%	Yes
CVE-2021-34523	Microsoft Exchange Server Privilege Escalation Vulnerability	100.0%	Yes
CVE-2023-29357	Microsoft SharePoint Server Privilege Escalation Vulnerability	100.0%	Yes

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