CVE-2025-21333

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: 10%CVSS: 7.8Exploit: cisa kev · ssvc active · epss top5pct · public exploitExposed: 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
10%
EPSS %ILE
95%
KEV
⚠ Exploited

Published

January 14, 2025

Last Modified

November 3, 2025

Advisory Details (5)

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-2025-21333
generic

CVE-2025-21333 - Elevated Privilege Exposure in Windows Hyper-V by Microsoft - Mitigation Script - vsociety

https://www.vicarius.io/vsociety/posts/cve-2025-21333-elevated-privilege-exposure-in-windows-hyper-v-by-microsoft-mitigation-script
generic

CVE-2025-21333 - Elevated Privilege Exposure in Windows Hyper-V by Microsoft - Detection Script - vsociety

https://www.vicarius.io/vsociety/posts/cve-2025-21333-elevated-privilege-exposure-in-windows-hyper-v-by-microsoft-detection-script
generic🟡 PoC Available

Microsoft Windows Server 2025 Hyper-V NT Kernel Integration VSP - Elevation of Privilege - Windows local Exploit

https://www.exploit-db.com/exploits/52436
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-2025-21333

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 94× in last 7d / 392× 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 1,434 total refreshes for this CVE.

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

Publicly available exploits

(3 references)

Working exploit code is in the public domain (2 GitHub PoCs) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCnu1lptr0/CVE-2025-21333
    First seen May 5, 2026

    LPE due to integer truncation in vskrnlintvsp.sys

    Open source ↗
  • Exploit-DBEDB-52436
    First seen Sep 16, 2025

    Microsoft Windows Server 2025 Hyper-V NT Kernel Integration VSP - Elevation of Privilege

    Open source ↗
  • GitHub PoCMrAle98/CVE-2025-21333-POC
    First seen Feb 27, 2025

    POC exploit for CVE-2025-21333 heap-based buffer overflow. It leverages WNF state data and I/O ring IOP_MC_BUFFER_ENTRY

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2025-21333?
CVE-2025-21333 is a critical vulnerability published on January 14, 2025. Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
When was CVE-2025-21333 disclosed?
CVE-2025-21333 was first published in the National Vulnerability Database on January 14, 2025, with the most recent update on November 3, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21333 actively exploited?
Yes. CISA added CVE-2025-21333 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-2025-21333?
CVE-2025-21333 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-2025-21333?
CVE-2025-21333 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-2025-21333?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21333, 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

Explore the affected products and dependency analysis for CVE-2025-21333

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