CVE-2026-66311

MEDIUMPre-NVD 6.26.2—
EchelonGraph scoreMEDIUM confidence

Score 6.2 from GitHub Security Advisory published 2026-08-04. The CNA's CVSS baseline 6.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
6.2EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 6.2Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Missing authorization in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering locally.

CVSS v3
6.2
EG Score
6.2MEDIUMmedium confidence
EG Risk
28
EG Risk 28/100CISA 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
Severity62% × 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
0.4%
EPSS %ILE
32nd
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 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-2026-66311

Vendor Advisories for CVE-2026-66311(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 17× in last 7d / 95× 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 242 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 02:30 UTCEG score recompute
  12. 2026-10-01 02:30 UTCVendor advisory
  13. 2026-10-01 02:30 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 06:29 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. 2026-09-23 23:52 UTCEG score recompute
  4. 2026-09-23 23:52 UTCVendor advisory
  5. 2026-09-23 23:52 UTCGHSA enrichment
  6. 2026-09-23 17:54 UTCEPSS rescore
  7. 2026-09-23 01:45 UTCEG score recompute
  8. 2026-09-23 01:45 UTCVendor advisory
  9. 2026-09-23 01:45 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 21:36 UTCEG score recompute
  14. 2026-09-20 21:36 UTCVendor advisory
  15. 2026-09-20 21:36 UTCGHSA enrichment
  16. 2026-09-20 20:16 UTCEPSS rescore
  17. 2026-09-19 23:25 UTCEG score recompute
  18. 2026-09-19 23:25 UTCVendor advisory
  19. 2026-09-19 23:25 UTCGHSA enrichment
  20. 2026-09-18 22:22 UTCEG score recompute
  21. 2026-09-18 22:22 UTCVendor advisory
  22. 2026-09-18 22:22 UTCGHSA enrichment
  23. 2026-09-18 19:28 UTCEPSS rescore
  24. 2026-09-17 22:42 UTCEG score recompute
  25. 2026-09-17 22:42 UTCVendor advisory
  26. 2026-09-17 22:41 UTCGHSA enrichment
  27. 2026-09-17 01:13 UTCEG score recompute
  28. 2026-09-17 01:13 UTCVendor advisory
  29. 2026-09-17 01:13 UTCGHSA enrichment
  30. 2026-09-16 14:08 UTCEPSS rescore
  31. 2026-09-16 05:15 UTCEPSS rescore
  32. 2026-09-15 16:52 UTCEG score recompute
  33. 2026-09-15 16:52 UTCVendor advisory
  34. 2026-09-15 16:52 UTCGHSA enrichment
  35. 2026-09-14 12:05 UTCEG score recompute
  36. 2026-09-14 12:05 UTCVendor advisory
  37. 2026-09-14 12:05 UTCGHSA enrichment
  38. 2026-09-13 13:59 UTCVendor advisory
  39. 2026-09-13 13:59 UTCGHSA enrichment
  40. 2026-09-12 15:53 UTCEG score recompute
  41. 2026-09-12 15:53 UTCVendor advisory
  42. 2026-09-12 15:53 UTCGHSA enrichment
  43. 2026-09-11 17:46 UTCEG score recompute
  44. 2026-09-11 17:46 UTCVendor advisory
  45. 2026-09-11 17:46 UTCGHSA enrichment
  46. 2026-09-11 14:53 UTCEPSS rescore
  47. 2026-09-11 09:37 UTCEPSS rescore
  48. 2026-09-10 19:11 UTCEG score recompute
  49. 2026-09-10 19:11 UTCGHSA enrichment
  50. 2026-09-09 21:04 UTCVendor advisory
  51. 2026-09-09 21:04 UTCGHSA enrichment
  52. 2026-09-09 19:37 UTCEG score recompute
  53. 2026-09-09 19:37 UTCVendor advisory
  54. 2026-09-09 19:37 UTCGHSA enrichment
  55. 2026-09-08 22:01 UTCEPSS rescore
  56. 2026-09-08 21:05 UTCGHSA enrichment
  57. 2026-09-08 17:09 UTCVendor advisory
  58. 2026-09-08 17:08 UTCGHSA enrichment
  59. 2026-09-07 18:45 UTCEG score recompute
  60. 2026-09-07 18:45 UTCVendor advisory
  61. 2026-09-07 18:45 UTCGHSA enrichment
  62. 2026-09-07 16:01 UTCEPSS rescore
  63. 2026-09-06 18:42 UTCEG score recompute
  64. 2026-09-06 18:42 UTCVendor advisory
  65. 2026-09-06 18:42 UTCGHSA enrichment
  66. 2026-09-06 13:47 UTCEPSS rescore
  67. 2026-09-05 20:35 UTCEG score recompute
  68. 2026-09-05 20:35 UTCVendor advisory
  69. 2026-09-05 20:35 UTCGHSA enrichment
  70. 2026-09-05 15:31 UTCEPSS rescore
  71. 2026-09-04 22:28 UTCVendor advisory
  72. 2026-09-04 22:27 UTCGHSA enrichment
  73. 2026-09-04 15:56 UTCEG score recompute
  74. 2026-09-04 15:56 UTCVendor advisory
  75. 2026-09-04 15:56 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66311?
CVE-2026-66311 is a medium vulnerability published on August 3, 2026. Missing authorization in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering locally.
When was CVE-2026-66311 disclosed?
CVE-2026-66311 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-2026-66311 actively exploited?
CVE-2026-66311 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (32nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66311?
CVE-2026-66311 has a CVSS base score of 6.2 (the CNA's own assessment, by microsoft; NVD's own analysis pending).
How do I remediate CVE-2026-66311?
A fix for CVE-2026-66311 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-66311 are linked in the Vendor Advisories panel on this page.

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