CVE-2021-41357

CRITICALNVD 7.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2022-04-25), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 7.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 5 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 2%CVSS: 7.8Exploit: cisa kev · ssvc activeExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Win32k Elevation of Privilege Vulnerability

CVSS v3
7.8
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

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
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
2%
EPSS %ILE
74%
KEV
⚠ Exploited

Published

October 13, 2021

Last Modified

October 30, 2025

Advisory Details (2)

Auto-updated Jun 3, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: microsoft, cisa.
cisa Patch Available🔴 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-2021-41357
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-2021-41357

Weakness Classification(1)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 106× in last 7d / 437× 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 1,649 total refreshes for this CVE.

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

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Frequently asked(6)

What is CVE-2021-41357?
CVE-2021-41357 is a critical vulnerability published on October 13, 2021. Win32k Elevation of Privilege Vulnerability
When was CVE-2021-41357 disclosed?
CVE-2021-41357 was first published in the National Vulnerability Database on October 13, 2021, with the most recent update on October 30, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-41357 actively exploited?
Yes. CISA added CVE-2021-41357 to the Known Exploited Vulnerabilities catalog on April 25, 2022, affecting Microsoft Win32k. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-41357?
CVE-2021-41357 has a CVSS v3 base score of 7.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2021-41357?
CVE-2021-41357 affects Microsoft Win32k. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-41357?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-41357, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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