CVE-2021-26424

CRITICALNVD 9.89.9▲
EchelonGraph scoreMEDIUM confidence

Score 9.9 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.1.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
9.9EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 61%
CISA-KEV: Not listedEPSS PROB: 61%CVSS: 9.8Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Windows TCP/IP Remote Code Execution Vulnerability

CVSS v3
9.8
EG Score
9.9CRITICALmedium confidence
EG Risk
74
EG Risk 74/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity99% × 45%
Exploitation61% × 40%
Automatability30% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
61%
EPSS %ILE
99th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

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

Exploitation public PoC (EG-KEV: elevated) · Automatable unknown (not published for this CVE) · Technical impact total (CVSS ≥ 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 12, 2021

Last Modified

August 10, 2026

Advisory Details (2)

Auto-updated Sep 28, 2026
Patch available. Sources: microsoft.
microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26424
microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26424

Vendor Advisories for CVE-2021-26424(2)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 23× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 146 total refreshes for this CVE.

  1. 2026-10-03 14:22 UTCEPSS rescore
  2. 2026-10-03 14:22 UTCEPSS rescore
  3. 2026-10-01 19:46 UTCEPSS rescore
  4. 2026-09-30 15:32 UTCEG score recompute
  5. 2026-09-30 15:00 UTCEPSS rescore
  6. 2026-09-26 15:54 UTCEPSS rescore
  7. 2026-09-26 15:54 UTCEPSS rescore
  8. 2026-09-24 14:00 UTCEPSS rescore
  9. 2026-09-23 13:44 UTCEPSS rescore
  10. 2026-09-21 20:28 UTCEPSS rescore
  11. 2026-09-18 19:23 UTCEPSS rescore
  12. 2026-09-17 19:23 UTCEPSS rescore
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  14. 2026-09-16 14:05 UTCEPSS rescore
  15. 2026-09-15 03:06 UTCEPSS rescore
  16. 2026-09-15 03:06 UTCEPSS rescore
  17. 2026-09-12 14:57 UTCEPSS rescore
  18. 2026-09-11 14:49 UTCEPSS rescore
  19. 2026-09-11 09:33 UTCEPSS rescore
  20. 2026-09-08 21:56 UTCEPSS rescore
  21. 2026-09-06 13:44 UTCEPSS rescore
  22. 2026-09-05 15:25 UTCEPSS rescore
  23. 2026-09-04 13:57 UTCEPSS rescore
  24. 2026-09-04 05:03 UTCEPSS rescore
  25. 2026-09-04 05:03 UTCEPSS rescore
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  1. 2026-09-02 14:08 UTCEPSS rescore
  2. 2026-08-30 19:14 UTCEPSS rescore
  3. 2026-08-28 21:37 UTCEPSS rescore
  4. 2026-08-27 14:22 UTCEPSS rescore
  5. 2026-08-26 14:42 UTCEPSS rescore
  6. 2026-08-25 13:45 UTCEPSS rescore
  7. 2026-08-24 14:12 UTCEPSS rescore
  8. 2026-08-21 23:46 UTCEPSS rescore
  9. 2026-08-20 22:52 UTCEPSS rescore
  10. 2026-08-19 17:01 UTCEPSS rescore
  11. 2026-08-18 13:45 UTCEPSS rescore
  12. 2026-08-17 13:44 UTCEPSS rescore
  13. 2026-08-16 02:11 UTCEPSS rescore
  14. 2026-08-16 02:11 UTCEPSS rescore
  15. 2026-08-15 01:27 UTCEPSS rescore
  16. 2026-08-13 21:57 UTCEPSS rescore
  17. 2026-08-12 13:47 UTCEPSS rescore
  18. 2026-08-11 13:38 UTCEPSS rescore
  19. 2026-08-10 16:32 UTCEG score recompute
  20. 2026-08-10 16:32 UTCGHSA enrichment
  21. 2026-08-10 16:19 UTCNVD updateCVSS v3 → 9.8
  22. 2026-08-10 15:50 UTCEG score recompute
  23. 2026-08-10 15:50 UTCGHSA enrichment
  24. 2026-08-08 16:33 UTCEPSS rescore
  25. 2026-08-07 16:23 UTCEPSS rescore
  26. 2026-08-05 19:14 UTCEPSS rescore
  27. 2026-08-03 10:33 UTCEPSS rescore
  28. 2026-07-30 01:28 UTCEPSS rescore
  29. 2026-07-30 01:27 UTCEPSS rescore
  30. 2026-07-28 15:33 UTCEPSS rescore
  31. 2026-07-26 14:52 UTCEPSS rescore
  32. 2026-07-26 14:52 UTCEPSS rescore
  33. 2026-07-25 14:15 UTCEPSS rescore
  34. 2026-07-24 14:15 UTCEPSS rescore
  35. 2026-07-23 14:16 UTCEPSS rescore
  36. 2026-07-23 01:58 UTCEG score recompute
  37. 2026-07-22 22:45 UTCEG score recompute
  38. 2026-07-22 14:06 UTCEPSS rescore
  39. 2026-07-22 14:06 UTCEPSS rescore
  40. 2026-07-21 15:22 UTCEPSS rescore
  41. 2026-07-21 15:22 UTCEPSS rescore
  42. 2026-07-20 17:05 UTCEPSS rescore
  43. 2026-07-19 02:27 UTCEPSS rescore
  44. 2026-07-19 02:27 UTCEPSS rescore
  45. 2026-07-16 17:00 UTCEPSS rescore
  46. 2026-07-15 16:55 UTCEPSS rescore
  47. 2026-07-15 16:55 UTCEPSS rescore
  48. 2026-07-13 22:27 UTCEPSS rescore
  49. 2026-07-13 22:27 UTCEPSS rescore
  50. 2026-07-13 06:10 UTCEPSS rescore
  51. 2026-07-12 05:44 UTCEPSS rescore
  52. 2026-07-12 05:44 UTCEPSS rescore
  53. 2026-07-11 08:25 UTCEPSS rescore
  54. 2026-07-11 08:25 UTCEPSS rescore
  55. 2026-07-09 19:07 UTCEPSS rescore
  56. 2026-07-08 15:12 UTCEPSS rescore
  57. 2026-07-06 02:21 UTCEPSS rescore
  58. 2026-07-06 02:21 UTCEPSS rescore
  59. 2026-07-04 06:29 UTCEPSS rescore
  60. 2026-07-04 06:29 UTCEPSS rescore
  61. 2026-07-02 16:57 UTCEPSS rescore
  62. 2026-07-01 15:03 UTCEPSS rescore
  63. 2026-06-30 23:20 UTCEPSS rescore
  64. 2026-06-30 23:20 UTCEPSS rescore
  65. 2026-06-29 14:04 UTCEPSS rescore
  66. 2026-06-28 04:54 UTCEPSS rescore
  67. 2026-06-28 04:54 UTCEPSS rescore
  68. 2026-06-27 03:06 UTCEPSS rescore
  69. 2026-06-27 03:06 UTCEPSS rescore
  70. 2026-06-25 13:48 UTCEPSS rescore
  71. 2026-06-25 13:48 UTCEPSS rescore
  72. 2026-06-24 14:03 UTCEPSS rescore
  73. 2026-06-24 14:03 UTCEPSS rescore
  74. 2026-06-23 21:31 UTCEPSS rescore
  75. 2026-06-23 21:31 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-26424?
CVE-2021-26424 is a critical vulnerability published on August 12, 2021. Windows TCP/IP Remote Code Execution Vulnerability
When was CVE-2021-26424 disclosed?
CVE-2021-26424 was first published on August 12, 2021, with the most recent update on August 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-26424 actively exploited?
CVE-2021-26424 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 61% probability of exploitation in the next 30 days (99th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-26424?
CVE-2021-26424 has a CVSS v3 base score of 9.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.9 (CRITICAL).
How do I remediate CVE-2021-26424?
A fix for CVE-2021-26424 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-26424 are linked in the Vendor Advisories panel on this page.

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