CVE-2026-70309

MEDIUMPre-NVD 5.45.4
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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: the CNA's CVSS, EPSS, GitHub Security Advisory
Trending — 4 sources updated this week

Also known asEUVD-2026-67853 (ENISA EUVD) · GHSA-j3c8-38vp-j837 (GitHub Security Advisories)Source: ENISA EUVD

5.4EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • 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 bypass a security feature over a network.

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

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity54% × 45%
Impact severity (EG Severity): CVSS 5.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
11th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.4): severity, escalated by confirmed exploitation. This CVE's 5.4 is its impact severity (EG Severity), not escalated.

EG Severity
5.4 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track 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). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 28, 2026

Last Modified

October 21, 2026

Advisory Details (1)

Auto-updated Aug 28, 2026
Patch available. Sources: microsoft.
MicrosoftMentions a patch (unverified)

Security Update Guide - Microsoft Security Response Center

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70309

Vendor Advisories for CVE-2026-70309(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 11× in last 7d / 78× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 216 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 116 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  2. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  3. 2026-10-25 14:08 UTCEG score recompute
  4. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  5. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  6. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  7. 2026-10-21 21:14 UTCEG score recompute
  8. 2026-10-21 21:14 UTCVendor advisory
  9. 2026-10-21 21:13 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  10. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  11. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  12. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  13. 2026-10-18 03:18 UTCEG score recompute
  14. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  15. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  16. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  17. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  18. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  19. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  20. 2026-10-12 15:44 UTCEG score recompute
  21. 2026-10-11 19:29 UTCEG score recompute
  22. 2026-10-11 16:44 UTCEG score recompute
  23. 2026-10-11 14:05 UTCEG score recompute
  24. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  25. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 10th percentile
Show 75 more
  1. 2026-10-10 00:50 UTCEG score recompute
  2. 2026-10-10 00:50 UTCVendor advisory
  3. 2026-10-10 00:50 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  4. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  5. 2026-10-08 19:07 UTCEG score recompute
  6. 2026-10-08 19:07 UTCVendor advisory
  7. 2026-10-08 19:07 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  8. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  9. 2026-10-08 00:51 UTCEG score recompute
  10. 2026-10-08 00:51 UTCVendor advisory
  11. 2026-10-08 00:51 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  13. 2026-10-06 17:11 UTCEG score recompute
  14. 2026-10-06 17:11 UTCVendor advisory
  15. 2026-10-06 17:11 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  16. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  17. 2026-10-05 18:24 UTCEG score recompute
  18. 2026-10-05 18:24 UTCVendor advisory
  19. 2026-10-05 18:24 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  20. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  22. 2026-10-04 19:36 UTCVendor advisory
  23. 2026-10-04 19:36 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  24. 2026-10-03 19:18 UTCEG score recompute
  25. 2026-10-03 19:18 UTCVendor advisory
  26. 2026-10-03 19:18 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  27. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  28. 2026-10-02 19:59 UTCEG score recompute
  29. 2026-10-02 19:59 UTCVendor advisory
  30. 2026-10-02 19:59 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  31. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  32. 2026-10-01 21:10 UTCEG score recompute
  33. 2026-10-01 21:10 UTCVendor advisory
  34. 2026-10-01 21:10 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  35. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  36. 2026-09-30 22:24 UTCEG score recompute
  37. 2026-09-30 22:24 UTCVendor advisory
  38. 2026-09-30 22:24 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  39. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  40. 2026-09-29 23:37 UTCEG score recompute
  41. 2026-09-29 23:37 UTCVendor advisory
  42. 2026-09-29 23:37 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  43. 2026-09-29 15:10 UTCEG score recompute
  44. 2026-09-29 15:10 UTCVendor advisory
  45. 2026-09-29 15:10 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  46. 2026-09-28 16:21 UTCEG score recompute
  47. 2026-09-28 16:21 UTCVendor advisory
  48. 2026-09-28 16:21 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  49. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  50. 2026-09-27 17:27 UTCEG score recompute
  51. 2026-09-27 17:27 UTCVendor advisory
  52. 2026-09-27 17:27 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  53. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  54. 2026-09-26 18:40 UTCEG score recompute
  55. 2026-09-26 18:40 UTCVendor advisory
  56. 2026-09-26 18:40 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  57. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  58. 2026-09-25 19:47 UTCVendor advisory
  59. 2026-09-25 19:46 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  60. 2026-09-25 12:41 UTCEG score recompute
  61. 2026-09-25 12:41 UTCVendor advisory
  62. 2026-09-25 12:41 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  63. 2026-09-24 13:54 UTCVendor advisory
  64. 2026-09-24 13:54 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  65. 2026-09-24 07:43 UTCEG score recompute
  66. 2026-09-24 07:43 UTCVendor advisory
  67. 2026-09-24 07:42 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  68. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  69. 2026-09-23 08:56 UTCEG score recompute
  70. 2026-09-23 08:56 UTCVendor advisory
  71. 2026-09-23 08:56 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  72. 2026-09-22 10:09 UTCEG score recompute
  73. 2026-09-22 10:09 UTCVendor advisory
  74. 2026-09-22 10:09 UTCGHSA enrichmentGHSA-j3c8-38vp-j837 · GitHub CVSS 5.4
  75. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.2% · 5th percentile

Frequently asked(5)

What is CVE-2026-70309?
CVE-2026-70309 is a medium-severity vulnerability; its CVE record was 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 made public?
CVE-2026-70309 was made public on August 28, 2026: that is the date its CVE record's CNA, Microsoft Corporation, gives for when the vulnerability was made public. The CVE record itself was published on August 28, 2026. EchelonGraph's copy of the record carries a last-modified date of October 21, 2026; the record at its source may have been updated since.
Is CVE-2026-70309 actively exploited?
CVE-2026-70309 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (11th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-70309?
CVE-2026-70309 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-2026-70309?
A fix for CVE-2026-70309 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-70309 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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