CVE-2025-21334

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: 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.

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
2%
EPSS %ILE
72%
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-2025-21334
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-2025-21334

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 91× in last 7d / 377× 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 907 total refreshes for this CVE.

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

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Frequently asked(6)

What is CVE-2025-21334?
CVE-2025-21334 is a critical vulnerability published on January 14, 2025. Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
When was CVE-2025-21334 disclosed?
CVE-2025-21334 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-2025-21334 actively exploited?
Yes. CISA added CVE-2025-21334 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-2025-21334?
CVE-2025-21334 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-2025-21334?
CVE-2025-21334 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-2025-21334?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21334, 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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