CVE-2024-21413

CRITICALNVD 9.89.8
EchelonGraph scoreHIGH confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score elevated to 9.8 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2025-02-06), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: CISA Known Exploited Vulnerabilities catalog, EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this weekExploited in the wild

Also known asEUVD-2024-19122 (ENISA EUVD) · GHSA-9mp4-h7q5-2rgq (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at low mission impact
CISA-KEV: ExploitedEPSS PROB: 95%CVSS: 9.8Exploit: Public PoCExposed services: Not assessed

A fix is available — apply it.

Microsoft Outlook Remote Code Execution Vulnerability

CVSS v3
9.8
EG Score
9.8CRITICALhigh confidence
EG Risk
99
EG Risk 99/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation100% × 40%
Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Attend at low mission impact; Act at medium or high.
Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it sooner than your standard update timelines at low mission impact and as soon as possible at medium or high.
EPSS PROB
95%
EPSS %ILE
99th
KEV
⚠ Exploited

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
95% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
CISA KEV and EG-KEV Tier 1 (exploited in the wild)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Act at medium mission impactAttend at low mission impact; Act at medium or high.CISA BOD 26-04: 3 days & forensic triage if the affected system is publicly exposed; 3 days & forensic triage if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Attend at low mission impact; Act at medium or high.

A fix is available. Apply it sooner than your standard update timelines at low mission impact and as soon as possible at medium or high.

Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days & forensic triage if the affected system is publicly exposed; 3 days & forensic triage if it is not.

The score's inputs: In CISA KEV yes (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

CISA required action“Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”

Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21413 · https://nvd.nist.gov/vuln/detail/CVE-2024-21413

Published

February 13, 2024

Last Modified

August 10, 2026

Advisory Details (5)

Auto-updated Oct 26, 2026
⚠️ Actively exploited (CISA KEV, CISA Vulnrichment). Patch available. Sources: microsoft.
Web page

CVE-2024-21413 - Critical "MonikerLink" Vulnerability Affecting Microsoft Outlook - Mitigation Script - vsociety

https://www.vicarius.io/vsociety/posts/cve-2024-21413-critical-monikerlink-vulnerability-affecting-microsoft-outlook-mitigation-script
Microsoft

Security Update Guide - Microsoft Security Response Center

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21413
CISA🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-21413
Web page

CVE-2024-21413 - Critical "MonikerLink" Vulnerability Affecting Microsoft Outlook - Detection Script - vsociety

https://www.vicarius.io/vsociety/posts/cve-2024-21413-critical-monikerlink-vulnerability-affecting-microsoft-outlook-detection-script
Web page

The Risks of the #MonikerLink Bug in Microsoft Outlook and the Big Picture - Check Point Research

https://research.checkpoint.com/2024/the-risks-of-the-monikerlink-bug-in-microsoft-outlook-and-the-big-picture/

Vendor Advisories for CVE-2024-21413(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 20× in last 7d / 183× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 1,803 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 1,703 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 22:38 UTCEG score recompute
  2. 2026-11-01 22:38 UTCVendor advisory
  3. 2026-11-01 22:37 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-11-01 16:31 UTCEPSS rescoreEPSS 95% · 99th percentile
  5. 2026-10-31 20:35 UTCEG score recompute
  6. 2026-10-31 20:35 UTCVendor advisory
  7. 2026-10-31 20:35 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-30 18:32 UTCEG score recompute
  9. 2026-10-30 18:32 UTCVendor advisory
  10. 2026-10-30 18:32 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-10-29 16:30 UTCEG score recompute
  12. 2026-10-29 16:30 UTCVendor advisory
  13. 2026-10-29 16:30 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-10-28 14:27 UTCEG score recompute
  15. 2026-10-28 14:27 UTCVendor advisory
  16. 2026-10-28 14:26 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-10-27 12:22 UTCEG score recompute
  18. 2026-10-27 12:21 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  19. 2026-10-26 10:19 UTCVendor advisory
  20. 2026-10-26 10:19 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-25 17:19 UTCEG score recompute
  22. 2026-10-25 16:30 UTCEPSS rescoreEPSS 95% · 99th percentile
  23. 2026-10-25 08:17 UTCEG score recompute
  24. 2026-10-25 08:17 UTCVendor advisory
  25. 2026-10-25 08:17 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
Show 75 more
  1. 2026-10-24 06:14 UTCEG score recompute
  2. 2026-10-24 06:14 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-10-23 04:12 UTCEG score recompute
  4. 2026-10-23 04:12 UTCVendor advisory
  5. 2026-10-23 04:11 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  6. 2026-10-22 02:04 UTCEG score recompute
  7. 2026-10-22 02:04 UTCVendor advisory
  8. 2026-10-22 02:04 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-10-21 16:29 UTCEPSS rescoreEPSS 95% · 99th percentile
  10. 2026-10-21 00:01 UTCEG score recompute
  11. 2026-10-21 00:01 UTCVendor advisory
  12. 2026-10-21 00:01 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-10-19 21:58 UTCEG score recompute
  14. 2026-10-19 21:58 UTCVendor advisory
  15. 2026-10-19 21:57 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-10-19 16:29 UTCEPSS rescoreEPSS 95% · 99th percentile
  17. 2026-10-18 19:54 UTCEG score recompute
  18. 2026-10-18 19:54 UTCVendor advisory
  19. 2026-10-18 19:54 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-18 16:29 UTCEPSS rescoreEPSS 95% · 99th percentile
  21. 2026-10-18 07:28 UTCEG score recompute
  22. 2026-10-17 17:50 UTCEG score recompute
  23. 2026-10-17 17:50 UTCVendor advisory
  24. 2026-10-17 17:50 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-16 16:36 UTCEPSS rescoreEPSS 95% · 99th percentile
  26. 2026-10-16 15:48 UTCEG score recompute
  27. 2026-10-16 15:48 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  28. 2026-10-15 13:43 UTCEG score recompute
  29. 2026-10-15 13:43 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  30. 2026-10-14 16:30 UTCEPSS rescoreEPSS 95% · 99th percentile
  31. 2026-10-14 11:40 UTCEG score recompute
  32. 2026-10-14 11:40 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  33. 2026-10-13 09:38 UTCVendor advisory
  34. 2026-10-13 09:37 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  35. 2026-10-12 18:03 UTCEG score recompute
  36. 2026-10-12 07:33 UTCVendor advisory
  37. 2026-10-12 07:32 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  38. 2026-10-12 03:44 UTCVendor advisory
  39. 2026-10-12 03:44 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  40. 2026-10-11 23:59 UTCVendor advisory
  41. 2026-10-11 23:58 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  42. 2026-10-11 20:12 UTCEG score recompute
  43. 2026-10-11 20:12 UTCVendor advisory
  44. 2026-10-11 20:12 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  45. 2026-10-11 16:26 UTCEG score recompute
  46. 2026-10-11 16:26 UTCVendor advisory
  47. 2026-10-11 16:26 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  48. 2026-10-11 16:21 UTCEG score recompute
  49. 2026-10-11 12:42 UTCEG score recompute
  50. 2026-10-11 12:42 UTCVendor advisory
  51. 2026-10-11 12:42 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  52. 2026-10-11 08:57 UTCVendor advisory
  53. 2026-10-11 08:56 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  54. 2026-10-11 05:10 UTCVendor advisory
  55. 2026-10-11 05:09 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  56. 2026-10-11 01:24 UTCVendor advisory
  57. 2026-10-11 01:24 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  58. 2026-10-10 21:40 UTCEG score recompute
  59. 2026-10-10 21:40 UTCVendor advisory
  60. 2026-10-10 21:40 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  61. 2026-10-10 19:58 UTCEPSS rescoreEPSS 95% · 99th percentile
  62. 2026-10-10 17:54 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  63. 2026-10-10 14:10 UTCVendor advisory
  64. 2026-10-10 14:10 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  65. 2026-10-10 10:25 UTCVendor advisory
  66. 2026-10-10 10:25 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  67. 2026-10-10 06:40 UTCVendor advisory
  68. 2026-10-10 06:40 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  69. 2026-10-10 02:56 UTCVendor advisory
  70. 2026-10-10 02:56 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  71. 2026-10-09 23:12 UTCEG score recompute
  72. 2026-10-09 23:12 UTCVendor advisory
  73. 2026-10-09 23:11 UTCGHSA enrichmentGHSA-9mp4-h7q5-2rgq · GitHub severity CRITICAL · GitHub CVSS 9.8
  74. 2026-10-09 20:05 UTCEPSS rescoreEPSS 95% · 99th percentile
  75. 2026-10-09 19:27 UTCVendor advisory

Publicly available exploits

(10 references)

Public exploit code is referenced for this CVE (10 GitHub PoCs). Defenders should treat patch urgency accordingly.

  • GitHub PoCmmathivanan17/CVE-2024-21413
    Published Nov 30, 2025

    Outlook exploitation

    Open source ↗
  • GitHub PoCD1se0/CVE-2024-21413-Vulnerabilidad-Outlook-LAB
    Published Dec 4, 2024
    Open source ↗
  • GitHub PoCThemeHackers/CVE-2024-21413
    Published Aug 31, 2024

    CVE-2024-21413 | Microsoft Outlook Remote Code Execution Vulnerability PoC

    Open source ↗
  • GitHub PoCdshabani96/CVE-2024-21413
    Published Feb 29, 2024
    Open source ↗
  • GitHub PoCahmetkarakayaoffical/CVE-2024-21413-Microsoft-Outlook-Remote-Code-Execution-Vulnerability
    Published Feb 23, 2024

    Bu betik, Microsoft Outlook'ta keşfedilen ve CVSS değeri 9.8 olan önemli bir güvenlik açığı olan CVE-2024-21413 için bir kavram kanıtı (PoC) sunmaktadır. MonikerLink hatası olarak adlandırılan bu güvenlik açığı, yerel NTLM bilgilerinin potansiyel sızıntısı ve uzaktan kod çalıştırma olasılığı dahil olmak üzere geniş kapsamlı etkilere sahiptir.

    Open source ↗
  • GitHub PoCMdusmandasthaheer/CVE-2024-21413-Microsoft-Outlook-Remote-Code-Execution-Vulnerability
    Published Feb 20, 2024
    Open source ↗
  • GitHub PoCCMNatic/CVE-2024-21413
    Published Feb 17, 2024

    CVE-2024-21413 PoC for THM Lab

    Open source ↗
  • GitHub PoCr00tb1t/CVE-2024-21413-POC
    Published Feb 16, 2024

    Microsoft Outlook Information Disclosure Vulnerability (leak password hash) - CVE-2024-21413 POC

    Open source ↗
  • GitHub PoCxaitax/CVE-2024-21413-Microsoft-Outlook-Remote-Code-Execution-Vulnerability
    Published Feb 16, 2024

    Microsoft-Outlook-Remote-Code-Execution-Vulnerability

    Open source ↗
  • GitHub PoCduy-31/CVE-2024-21413
    Published Feb 15, 2024

    Microsoft Outlook Information Disclosure Vulnerability (leak password hash) - Expect Script POC

    Open source ↗

Frequently asked(6)

What is CVE-2024-21413?
CVE-2024-21413 is a critical-severity vulnerability; its CVE record was published on February 13, 2024. Microsoft Outlook Remote Code Execution Vulnerability
When was CVE-2024-21413 made public?
CVE-2024-21413 was made public on February 13, 2024: that is the date its CVE record's CNA, Microsoft Corporation, gives for when the vulnerability was made public. The CVE record itself was published on February 13, 2024. EchelonGraph's copy of the record carries a last-modified date of August 10, 2026; the record at its source may have been updated since.
Is CVE-2024-21413 actively exploited?
Yes. CISA added CVE-2024-21413 to the Known Exploited Vulnerabilities catalog on February 6, 2025, affecting Microsoft Office Outlook. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is available. Apply it.
What is the CVSS score of CVE-2024-21413?
CVE-2024-21413 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2024-21413?
CVE-2024-21413 affects Microsoft Office Outlook.
How do I remediate CVE-2024-21413?
A fix for CVE-2024-21413 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2024-21413 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2024-21413

Explore →

Is Your Infrastructure Affected by CVE-2024-21413?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.