CVE-2026-66316

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

Score 5.4 from GitHub Security Advisory published 2026-08-04. The CNA's CVSS baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

CVSS v3
5.4
EG Score
5.4MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100CISA SSVC

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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
10th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 3, 2026

Last Modified

September 25, 2026

Advisory Details (1)

Auto-updated Aug 4, 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-2026-66316

Vendor Advisories for CVE-2026-66316(2)

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 18× in last 7d / 92× 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 225 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66316?
CVE-2026-66316 is a medium vulnerability published on August 3, 2026. Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform spoofing over a network.
When was CVE-2026-66316 disclosed?
CVE-2026-66316 was first published on August 3, 2026, with the most recent update on September 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66316 actively exploited?
CVE-2026-66316 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (10th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66316?
CVE-2026-66316 has a CVSS base score of 5.4 (the CNA's own assessment, by microsoft; NVD's own analysis pending).
How do I remediate CVE-2026-66316?
A fix for CVE-2026-66316 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-66316 are linked in the Vendor Advisories panel on this page.

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