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Vulnerabilities/CVE-2024-21413
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CVE-2024-21413

Microsoft Outlook Remote Code Execution Vulnerability

VendormicrosoftPublishedFeb 13, 2024SourceNVDWeaknessCWE-20
Act now

Actively exploited in the wild. Patch or mitigate immediately — don't wait for a maintenance window.

Severity
Critical · 9.8
CVSS base score
Exploitation
In the wild
CISA KEV
Predicted risk
95% model
EPSS forecast — overtaken by confirmed exploitation
Exposure
Internet-facing
Exploitable remotely, no login, no user action
01

What's the risk?

An unauthenticated attacker, remotely over the network, with no user interaction, can fully compromise the system — steal data, tamper with it and take it offline.

Microsoft Outlook Remote Code Execution Vulnerability

How it's exploitedMITRE ATT&CK · inferred from weakness & vector
Initial Access
T1190Exploit Public-Facing Application

Inferred from the weakness type (CWE) and how the flaw is reached — the techniques an attacker would chain to exploit this. Real-world corroboration appears here as threat intel is folded in.

02

Who's exploiting it?

Corroborated threat activity referencing this CVE — with source and confidence, not inference.

Confirmed exploited in the wild. CISA KEV · catalogued Feb 6, 2025

Named threat actors and observed ATT&CK techniques appear here as intel feeds are folded in — the ATT&CK chain above stays inferred until then.

03

Are we affected?

6
  • Affectedmicrosoft · 365_appsall versions
  • Affectedmicrosoft · office_2016all versions
  • Affectedmicrosoft · office_2016all versions
  • Affectedmicrosoft · office_2019
all versions
  • Affectedmicrosoft · office_2019all versions
  • Affectedmicrosoft · office_long_term_servicing_channel2021
  • 04

    What to do

    Generated by Wavense from the CVE record — an immediate mitigation and the permanent fix.

    1. !

      Mitigate now

      Until patches can be deployed, implement strict email gateway filtering to block suspicious attachments and enforce strong email security policies. Deploy Endpoint Detection and Response (EDR) solutions to monitor for unusual outbound connections or suspicious process activity originating from Outlook clients, and consider implementing Extended Protection for Authentication where applicable.

    2. ✓

      Permanent fix

      The permanent resolution is to apply the security updates released by Microsoft immediately. Ensure all affected Microsoft Outlook installations and the underlying Windows operating systems are updated to the latest patched versions to fully remediate this critical remote code execution vulnerability.

    Technical details— weakness, CVSS vector & calculator, related CVEs

    Business impact

    This critical vulnerability allows an unauthenticated attacker to achieve remote code execution on a victim's machine without user interaction in some scenarios. Successful exploitation can lead to full system compromise, data theft, installation of malware, and the ability to pivot to other systems within the network, resulting in severe data breaches and operational disruption.

    Weakness

    1
    CWE-20Common Weakness Enumeration · MITRE definition

    CVSS 3.1 details

    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    0.0
    / 10.0 base
    Critical severity
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Exploitability metrics
    Attack VectorAV
    Remotely exploitable across a network
    Attack ComplexityAC
    No special conditions required
    Privileges RequiredPR
    No authorization needed
    User InteractionUI
    No user participation needed
    Impact metrics
    ScopeS
    Impact confined to the vulnerable component
    ConfidentialityC
    Total loss of confidentiality
    IntegrityI
    Total loss of integrity
    AvailabilityA
    Total loss of availability

    Related vulnerabilities

    Other CVEs affecting 365 apps

    NVD
    9.8Critical
    CVE-2023-23397KEVExploit likely

    Microsoft Outlook Elevation of Privilege Vulnerability

    microsoftCWE-20Improper Input ValidationNetworkLow effortNo authNo interactionCIA
    2023-03-14
    NVD
    8.8High
    CVE-2024-38189KEV

    Microsoft Project Remote Code Execution Vulnerability

    microsoftCWE-20Improper Input ValidationNetworkLow effortNo authUser neededCIA
    2024-08-13
    NVD
    8.8High
    CVE-2023-35311KEV

    Microsoft Outlook Security Feature Bypass Vulnerability

    microsoftCWE-367TOCTOU Race ConditionNetworkLow effortNo authUser neededCIA
    2023-07-11
    NVD
    7.8High
    CVE-2026-21514KEV

    Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to bypass a security feature locally.

    microsoftCWE-807LocalLow effortNo authUser neededCIA
    2026-02-10
    NVD
    7.8High
    CVE-2026-21509KEVExploit likely

    Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.

    microsoftCWE-807LocalLow effortNo authUser neededCIA
    2026-01-26
    NVD
    7.8High
    CVE-2021-42292KEV

    Microsoft Excel Security Feature Bypass Vulnerability

    microsoftLocalLow effortNo authUser neededCIA
    2021-11-10
    NVD
    7.8High
    CVE-2021-38646KEV

    Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability

    microsoftLocalLow effortNo authUser neededCIA
    2021-09-15
    NVD
    7.6High
    CVE-2021-27059KEV

    Microsoft Office Remote Code Execution Vulnerability

    microsoftNetworkHigh effortAdmin privUser neededCIA
    2021-03-11
    0.0
    / 10.0 base
    Critical severity
    Key facts
    CVE ID
    CVE-2024-21413
    Published
    Feb 13, 2024
    Last modified
    Aug 10, 2026
    CVSS
    9.8 (v3.1)
    EPSS
    94.66%
    In CISA KEV
    Yes
    Confidence
    100/100
    Weakness
    CWE-20
    Timeline
    1. Feb 13, 2024Published to NVDNVD
    2. Aug 10, 2026Record last modifiedNVD
    3. Aug 18, 2026AI analysis generatedWavense
    View on NVD