CVE-2024-21413

Published Feb 13, 2024

Last updated 6 months ago

Overview

AI description

Automated description summarized from trusted sources.

CVE-2024-21413 is a remote code execution (RCE) vulnerability affecting Microsoft Outlook. It stems from improper input validation when Outlook processes URLs, particularly those using the `file://` protocol and crafted URL structures. This vulnerability, also known as the "MonikerLink" bug, allows attackers to bypass security protections, such as the Office Protected View, and execute arbitrary code on a victim's machine by sending a malicious email. The vulnerability can be triggered even when previewing a maliciously crafted email. Successful exploitation could lead to remote code execution, theft of NTLM credentials, data exfiltration, data encryption, installation of malware, and potential full system compromise. It affects various versions of Microsoft Outlook, including Microsoft Office 2016, 2019, 2021, and Microsoft 365 Apps.

Description
Microsoft Outlook Remote Code Execution Vulnerability
Source
secure@microsoft.com
NVD status
Analyzed
Products
365_apps, office_2016, office_2019, office_long_term_servicing_channel

Risk scores

CVSS 3.1

Type
Secondary
Base score
9.8
Impact score
5.9
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity
CRITICAL

Known exploits

Data from CISA

Vulnerability name
Microsoft Outlook Improper Input Validation Vulnerability
Exploit added on
Feb 6, 2025
Exploit action due
Feb 27, 2025
Required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Weaknesses

secure@microsoft.com
CWE-20
nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending
  1. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/dDkNFlyWGq #tryhackme via @tryhackme

    @HafzKhalil

    9 May 2026

    19 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  2. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/PnvhVuuh9S #tryhackme via @tryhackme

    @mhmdalq02

    8 May 2026

    31 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  3. I started the exploitation basics module on THM! (CVE-2024-21413) covers a vulnerability in Outlook that allowed attackers to bypass security by adding "!" to a file:// link in an email. Once clicked, it could steal your NTLM credentials. Metasploit is a powerful tool that http

    @Ogechee_

    6 May 2026

    1694 Impressions

    6 Retweets

    60 Likes

    6 Bookmarks

    2 Replies

    0 Quotes

  4. CVE-2024-21413. Status: ✅ Confirmed exploited in the wild Date added: 2025-02-06 Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

    @lyrie_ai

    4 May 2026

    45 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    1 Reply

    0 Quotes

  5. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/CuHhd3kwQu #tryhackme via @tryhackme

    @CreamjamBird

    22 Apr 2026

    38 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  6. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/rFMHY02ffE #tryhackme via @tryhackme

    @profession32384

    20 Apr 2026

    4 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  7. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/nFE31geDx0 #tryhackme via @tryhackme

    @SangAlberto

    17 Apr 2026

    14 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  8. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/lIqPqz957i #tryhackme via @tryhackme

    @DEDSEC0025

    17 Apr 2026

    44 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  9. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/Xhva2jW3rW #tryhackme через @tryhackme

    @rickert155

    10 Apr 2026

    66 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    1 Quote

  10. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/WjjSKgnGmo #tryhackme via @tryhackme

    @ToheebDev

    6 Apr 2026

    42 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  11. https://t.co/vJqqefVaec Microsoft Outlookにおいて、特定リンクをクリックするだけでリモートコード実行(RCE)が可能になる致命的な脆弱性(CVE-2024-21413)が報告されています。必ず最新のセキュリティ更新を適用してくだ

    @Anti_Ch_PCgc

    2 Apr 2026

    89 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  12. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/LN7DqrjwDk #tryhackme via @tryhackme

    @debmahato8967

    25 Mar 2026

    35 Impressions

    0 Retweets

    1 Like

    0 Bookmarks

    0 Replies

    0 Quotes

  13. Day 45: 🔗CVE-2024-21413 (Moniker Link): Diving deep into how a simple Outlook hyperlink can bypass Protected View to leak NTLM hashes or trigger RCE. 🛠️

    @dheeraditya1

    18 Mar 2026

    30 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    1 Reply

    0 Quotes

  14. Outlook RCE CVE-2024-21413 (CVSS 9.8) is HOT! Malicious links exploit NTLM relay via preview pane for RCE. Think targeted phishing, but without a click. Exploit using Responder/Impacket. #Outlook #RCE #Cybersecurity https://t.co/BjeGzZHgIR

    @computerauditor

    17 Mar 2026

    43 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  15. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/k0pdHWw7WT #tryhackme via @tryhackme

    @Jasmin03897025

    17 Mar 2026

    54 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  16. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/87RysCQWhk #tryhackme via @tryhackme

    @dronjx

    16 Mar 2026

    60 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  17. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/6mcGNF0J6B #tryhackme via @tryhackme

    @lerchmirko

    14 Mar 2026

    71 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  18. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/bT1Aoqvy7R

    @Ryad3135

    11 Mar 2026

    37 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  19. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/96Zk5MF9yT #tryhackme via @tryhackme

    @XaliqRagimli27

    10 Mar 2026

    65 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  20. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/7rjTiv9kYO #tryhackme via @tryhackme

    @chuol_hoth

    28 Feb 2026

    59 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  21. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/UUeK4V6W0z #tryhackme via @tryhackme

    @mgillanders

    28 Feb 2026

    48 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  22. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/Eu6ilZW3mh #tryhackme via @tryhackme

    @KuriJMandara

    26 Feb 2026

    41 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  23. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/Eu6ilZVvwJ #tryhackme via @tryhackme

    @KuriJMandara

    26 Feb 2026

    39 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  24. 🚨 [CRITICAL] APT29 OAuth Token Theft Campaign APT29 actively exploiting OAuth token theft t… 🔴 CVE: CVE-2024-21413 🕵️ APT: APT29 🏭 Sectors: finance, government #mysocAi #CyberSecurityusingAi #ThreatIntel #CVE202421413 🔗 https://t.co/1VmtnQVX6T

    @MysocAi

    23 Feb 2026

    1 Impression

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  25. 🚨 [CRITICAL] APT29 OAuth Token Theft Campaign APT29 actively… 🔴 CVE: CVE-2024-21413 🕵️ APT: APT29 🏭 Sectors: finance, government #mysocAi #CyberSecurityusingAi #Vulnerability #Criticality #ThreatIntel #CVE202421413 🔗 https://t.co/1VmtnQVX6T

    @MysocAi

    23 Feb 2026

    2 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  26. 🚨 [CRITICAL] APT29 Midnight Blizzard Active Campaign via OAuth Token Theft … 🔴 CVE: CVE-2024-21413, CVE-2024-20671 🕵️ APT: APT29 🏭 Sectors: finance, government #mysocAi #CyberSecurityusingAi #Vulnerability #Criticality #ThreatIntel #CyberSecurity #CVE202421413

    @MysocAi

    23 Feb 2026

    1 Impression

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  27. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/k8il1CJ4og #tryhackme via @tryhackme

    @Mr_ajitsharma74

    22 Feb 2026

    3 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  28. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/M3D111EzAJ #tryhackme @tryhackmeより

    @Sirai_Tukuyomi

    21 Feb 2026

    44 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  29. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/ahRjmwCiSp #tryhackme via @tryhackme

    @White_Crow017

    20 Feb 2026

    54 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  30. Just learned how CVE-2024-21413 (Moniker Link vuln) works and it’s wild 🤯 Outlook renders HTML emails → attacker embeds a file:// link → adds a special ! trick → bypasses Protected View → Windows auto-authenticates via SMB → leaks NTLM hash 😬 No malware. Just a

    @White_Crow017

    20 Feb 2026

    106 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  31. Day 108 of learning Cybersecurity on TryHackMe, I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/J1ozAD0YTS #tryhackme via @tryhackme

    @DGilcore

    19 Feb 2026

    58 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  32. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! An Outlook's vulnerability in 2024 that leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/J1ozAD0YTS #tryhackme via @tryhackme @ireteeh @Adanna_techie @AdePelumi15 https

    @DGilcore

    19 Feb 2026

    85 Impressions

    1 Retweet

    2 Likes

    1 Bookmark

    1 Reply

    0 Quotes

  33. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/jIq09hIs1e #tryhackme via @tryhackme

    @lumentraaa

    15 Feb 2026

    40 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  34. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/5Sy9eiWyvk #tryhackme via @tryhackme

    @YMoriati42377

    13 Feb 2026

    37 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  35. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/t6qJmMgLNS #tryhackme via @tryhackme

    @quek_guan

    8 Feb 2026

    48 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  36. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/6xUmCMcDdm #tryhackme via @tryhackme

    @Althaf1145

    6 Feb 2026

    45 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  37. The NTLM leak vulnerability (CVE-2024-21413): User receives email with link: file://attacker.com/share!\ User clicks. Windows: "Oh, a file share. Let me authenticate." Windows sends: Username + NTLM hash to attacker's server Attacker cracks hash offline One click. Full compromise

    @SALIMASSILI2006

    5 Feb 2026

    47 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  38. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! https://t.co/igg97EGdwm

    @saaramhussnain

    5 Feb 2026

    58 Impressions

    0 Retweets

    3 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  39. 1️⃣ One character bypasses Microsoft security CVE-2024-21413: Add ! to a file:// link in Outlook. User clicks. Windows automatically leaks NTLM credentials. No download. No warning. CVSS 9.8 = critical. One character = Entire network compromised. https://t.co/p3ljypv97E

    @SALIMASSILI2006

    3 Feb 2026

    57 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  40. One character can steal your password. Just ! in a file:// link = Windows leaks NTLM credentials. CVE-2024-21413 | CVSS 9.8 Small detail = Massive impact. This is why SOC analysts obsess over "minor" things. #CyberSecurity #SOCAnalyst #ThreatIntel https://t.co/YI8IKuDhuR

    @SALIMASSILI2006

    3 Feb 2026

    66 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  41. Happy new month 🎉 February is here and the grind continues. Wrapped up the Moniker Link module (CVE-2024-21413). Learned how Outlook can leak NTLM hashes via Moniker Links and how to defend against it. #Cybersecurity #LearningInPublic #TechJourney https://t.co/aYMQMi4qlx

    @jeo_crypts

    2 Feb 2026

    55 Impressions

    1 Retweet

    2 Likes

    0 Bookmarks

    1 Reply

    0 Quotes

  42. 📢 𝐇𝐨𝐭 𝐨𝐟𝐟 𝐭𝐡𝐞 𝐩𝐫𝐞𝐬𝐬: 𝐂𝐕𝐄 𝐢𝐧𝐬𝐢𝐠𝐡𝐭𝐬! Discover how UAC-0028 exploits CVE-2024-21413 in Outlook to steal credentials and bypass defenses, with CERT-UA insights and actionable mitigations. 🌐 Explore the

    @PurpleOps_io

    2 Feb 2026

    41 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  43. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/xXyriTmL53 #tryhackme via @tryhackme

    @SultryIce

    31 Jan 2026

    71 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  44. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/yHnA3kLK5h #tryhackme via @tryhackme

    @pooping4poops

    30 Jan 2026

    50 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  45. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/0P3MEzDC6V #tryhackme via @tryhackme

    @J3CHxP

    27 Jan 2026

    43 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  46. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe. Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/h0icCCtgXX #tryhackme via @tryhackme

    @mallox_318

    25 Jan 2026

    0 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  47. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe. Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/l5wmJlWHhw #tryhackme via @tryhackme

    @MrKiyan404

    22 Jan 2026

    104 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  48. Day 16: my journey on @tryhackme alongside @d4rk_intel > Moniker link Deep dive into CVE-2024-21413, Explored how crafted Outlook links bypass Protected View, enabling credential leaks and potential RCE, alongside detection and mitigation in a lab environment. #cybersecurit

    @Azutech_

    22 Jan 2026

    349 Impressions

    0 Retweets

    7 Likes

    0 Bookmarks

    1 Reply

    0 Quotes

  49. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe! Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/40iFhXR2Lq #tryhackme via @tryhackme

    @RedionMeta

    20 Jan 2026

    40 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

  50. I just completed Moniker Link (CVE-2024-21413) room on TryHackMe. Leak user's credentials using CVE-2024-21413 to bypass Outlook's Protected View. https://t.co/n70Qrl6uev #tryhackme via @tryhackme

    @JayeshV88153533

    19 Jan 2026

    58 Impressions

    0 Retweets

    0 Likes

    0 Bookmarks

    0 Replies

    0 Quotes

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