CVE-2026-70309

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreHIGH confidence

Score 5.4 from GitHub Security Advisory published 2026-08-28. 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%CVSS: 5.4Exploit: 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 bypass a security feature over a network.

CVSS v3
5.4
EG Score
5.4(high)
EG Risk
24(Track)
EG Risk 24/100SSVC: 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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

August 28, 2026

Last Modified

September 16, 2026

Advisory Details (1)

Auto-updated Aug 28, 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-2026-70309

Vendor Advisories for CVE-2026-70309(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 27× in last 7d / 109× 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 109 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-70309?
CVE-2026-70309 is a medium vulnerability published on August 28, 2026. Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to bypass a security feature over a network.
When was CVE-2026-70309 disclosed?
CVE-2026-70309 was first published in the National Vulnerability Database on August 28, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-70309 actively exploited?
CVE-2026-70309 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 94.6% of all scored CVEs.
What is the CVSS score of CVE-2026-70309?
CVE-2026-70309 has a CVSS v4.0 base score of 5.4 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-70309?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-70309, 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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