CVE-2026-40369

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-05-12. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
7.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 5%CVSS: 7.8Exploit: NoneExposed: 0

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

Heap-based buffer overflow in Windows Kernel allows an authorized attacker to elevate privileges locally.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
51(Track)
EG Risk 51/100SSVC: Track

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
Severity78% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
90.9%
KEV
Not listed

Published

May 12, 2026

Last Modified

June 26, 2026

Advisory Details (1)

Auto-updated May 12, 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://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40369

Vendor Advisories for CVE-2026-40369(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 44× 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 162 total refreshes for this CVE.

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

Publicly available exploits

(2 references)

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

  • GitHub PoCpiffd0s/ntoskrnl-metadata
    First seen May 22, 2026

    eprocess offset puller for relevant member offsets and function addresses for cve-2026-40369

    Open source ↗
  • GitHub PoCorinimron123/CVE-2026-40369-EXPLOIT
    First seen May 13, 2026

    Full exploit code for CVE-2026-40369 - A Windows kernel arbitrary write vulnerability that allows browser sandbox escape from all browsers render process sandbox

    Open source ↗

Frequently asked(5)

What is CVE-2026-40369?
CVE-2026-40369 is a high vulnerability published on May 12, 2026. Heap-based buffer overflow in Windows Kernel allows an authorized attacker to elevate privileges locally.
When was CVE-2026-40369 disclosed?
CVE-2026-40369 was first published in the National Vulnerability Database on May 12, 2026, with the most recent update on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40369 actively exploited?
CVE-2026-40369 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 90.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40369?
CVE-2026-40369 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-40369?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40369, 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-2026-40369

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