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, ghsa
Trending — Patch released 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
19(Track)
EG Risk 19/100SSVC: 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%
Exploitation0% × 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

August 29, 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 21× in last 7d / 21× 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.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 16:36 UTCEG score recompute
  3. 2026-08-29 16:36 UTCVendor advisory
  4. 2026-08-29 16:36 UTCGHSA enrichment
  5. 2026-08-29 04:27 UTCEG score recompute
  6. 2026-08-29 04:27 UTCVendor advisory
  7. 2026-08-29 04:26 UTCGHSA enrichment
  8. 2026-08-29 04:05 UTCEG score recompute
  9. 2026-08-29 04:05 UTCVendor advisory
  10. 2026-08-29 04:05 UTCGHSA enrichment
  11. 2026-08-28 22:45 UTCEG score recompute
  12. 2026-08-28 22:45 UTCVendor advisory
  13. 2026-08-28 22:44 UTCGHSA enrichment
  14. 2026-08-28 22:09 UTCEG score recompute
  15. 2026-08-28 22:09 UTCVendor advisory
  16. 2026-08-28 22:09 UTCGHSA enrichment
  17. 2026-08-28 20:25 UTCEG score recompute
  18. 2026-08-28 20:25 UTCVendor advisory
  19. 2026-08-28 19:38 UTCEG score recompute
  20. 2026-08-28 19:38 UTCVendor advisory
  21. 2026-08-28 19:36 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor + same CWE)

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 August 29, 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 55.5% 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

Explore the affected products and dependency analysis for CVE-2026-66798

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