CVE-2026-66318

HIGHPre-NVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2026-08-04. the CNA's CVSS baseline 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.1Exploit: None knownExposed: 0

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

Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to disclose information over a network.

CVSS v3
8.1
EG Score
8.1(medium)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity81% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
16%
KEV
Not listed

Published

August 3, 2026

Last Modified

September 17, 2026

Advisory Details (1)

Auto-updated Aug 3, 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-2026-66318

Vendor Advisories for CVE-2026-66318(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.

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 35× in last 7d / 159× 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 290 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-66318?
CVE-2026-66318 is a high vulnerability published on August 3, 2026. Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to disclose information over a network.
When was CVE-2026-66318 disclosed?
CVE-2026-66318 was first published in the National Vulnerability Database on August 3, 2026, with the most recent update on September 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66318 actively exploited?
CVE-2026-66318 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 84.3% of all scored CVEs.
What is the CVSS score of CVE-2026-66318?
CVE-2026-66318 has a CVSS v4.0 base score of 8.1 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-66318?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66318, 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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