CVE-2026-66302

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-08. the CNA's CVSS baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: None knownExposed: 0

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

External control of file name or path in Skype for Business allows an unauthorized attacker to execute code over a network.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
59(Track)
EG Risk 59/100SSVC: 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
Severity98% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
44%
KEV
Not listed

Published

September 8, 2026

Last Modified

September 18, 2026

Advisory Details (1)

Auto-updated Sep 18, 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-2026-66302

Vendor Advisories for CVE-2026-66302(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 99× in last 7d / 165× 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 165 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-66302?
CVE-2026-66302 is a critical vulnerability published on September 8, 2026. External control of file name or path in Skype for Business allows an unauthorized attacker to execute code over a network.
When was CVE-2026-66302 disclosed?
CVE-2026-66302 was first published in the National Vulnerability Database on September 8, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66302 actively exploited?
CVE-2026-66302 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 56.1% of all scored CVEs.
What is the CVSS score of CVE-2026-66302?
CVE-2026-66302 has a CVSS v4.0 base score of 9.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-66302?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66302, 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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