CVE-2026-66798

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreHIGH confidence

Score 4.3 from GitHub Security Advisory published 2026-08-28. the CNA's CVSS baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — 4 sources updated this week
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 4.3Exploit: None knownExposed: 0

A fix is available — apply it.

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

CVSS v3
4.3
EG Score
4.3(high)
EG Risk
20(Track)
EG Risk 20/100SSVC: 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
Severity43% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
45%
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-2026-66798

Vendor Advisories for CVE-2026-66798(7)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrhacm2/cluster-backup-rhel9-operator:17876846682026-08-26redhat
redhatrhacm2/cluster-backup-rhel9-operator:17872590602026-08-26redhat
redhatrhacm2/cluster-backup-rhel9-operator:17871831782026-08-26redhat
redhatrhacm2/cluster-backup-rhel9-operator:17872385002026-08-26redhat
redhatrhacm2/cluster-backup-rhel9-operator:17871831762026-08-26redhat
redhatrhacm2/cluster-backup-rhel9-operator:17872275762026-08-26redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 24× in last 7d / 117× 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 117 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-66798?
CVE-2026-66798 is a medium vulnerability published on August 28, 2026. Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.
When was CVE-2026-66798 disclosed?
CVE-2026-66798 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-2026-66798 actively exploited?
CVE-2026-66798 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 54.8% of all scored CVEs.
What is the CVSS score of CVE-2026-66798?
CVE-2026-66798 has a CVSS v4.0 base score of 4.3 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-66798?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66798, 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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