CVE-2025-21335

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 2025-01-14), 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: 1%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.

Windows Hyper-V NT Kernel Integration VSP 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
1%
EPSS %ILE
71%
KEV
⚠ Exploited

Published

January 14, 2025

Last Modified

October 27, 2025

Advisory Details (2)

Auto-updated Jun 4, 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-2025-21335
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-2025-21335

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 100× in last 7d / 424× 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 1,570 total refreshes for this CVE.

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

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Frequently asked(6)

What is CVE-2025-21335?
CVE-2025-21335 is a critical vulnerability published on January 14, 2025. Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
When was CVE-2025-21335 disclosed?
CVE-2025-21335 was first published in the National Vulnerability Database on January 14, 2025, with the most recent update on October 27, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21335 actively exploited?
Yes. CISA added CVE-2025-21335 to the Known Exploited Vulnerabilities catalog on January 14, 2025, affecting Microsoft Windows. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2025-21335?
CVE-2025-21335 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-2025-21335?
CVE-2025-21335 affects Microsoft Windows. 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-2025-21335?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21335, 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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