CVE-2026-66794

CRITICALPre-NVD 9.39.3—
EchelonGraph scoreMEDIUM confidence

Score 9.3 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-19. a secondary CVSS source baseline 9.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
9.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.3Exploit: None knownExposed: 0

A fix is available — apply it.

A flaw was found in the cluster-proxy-addon component of Multicluster Engine for Kubernetes. This vulnerability allows an unauthenticated attacker, who can access the user-facing route, to bypass authentication and authorization checks. By manipulating URL path segments, the attacker can proxy requests to arbitrary services across any managed cluster. This enables unauthorized access to internal services that would otherwise be protected, potentially leading to information disclosure or further compromise of the cluster environment.

CVSS v3
9.3
EG Score
9.3(medium)
EG Risk
57(Track)
EG Risk 57/100SSVC: 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
Severity93% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
35%
KEV
Not listed

Published

August 19, 2026

Last Modified

September 8, 2026

Advisory Details (8)

Auto-updated Sep 14, 2026
Patch available. Sources: redhat.
redhat

2507539 – (CVE-2026-66794) CVE-2026-66794 cluster-proxy-addon: cluster-proxy-addon: unauthenticated SSRF to arbitrary managed-cluster services via public Route

https://bugzilla.redhat.com/show_bug.cgi?id=2507539
redhat Patch Available

CVE-2026-66794 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-66794
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:59593
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:59579
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:59559
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:59558
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:59557
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:59556

Vendor Advisories for CVE-2026-66794(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
redhatmulticluster-engine/cluster-proxy-addon-rhel9:17871733612026-08-25redhat
redhatmulticluster-engine/cluster-proxy-addon-rhel9:17872753182026-08-25redhat
redhatmulticluster-engine/cluster-proxy-addon-rhel9:17872755192026-08-25redhat
redhatmulticluster-engine/cluster-proxy-addon-rhel9:17872749232026-08-25redhat
redhatmulticluster-engine/cluster-proxy-rhel9:17872767842026-08-25redhat
redhatmulticluster-engine/cluster-proxy-rhel9:17869833492026-08-25redhat

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.

Data Freshness Timeline

(refreshed 90× in last 7d / 379× 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 386 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-66794?
CVE-2026-66794 is a critical vulnerability published on August 19, 2026. A flaw was found in the cluster-proxy-addon component of Multicluster Engine for Kubernetes. This vulnerability allows an unauthenticated attacker, who can access the user-facing route, to bypass authentication and authorization checks. By manipulating URL path segments, the attacker can proxy…
When was CVE-2026-66794 disclosed?
CVE-2026-66794 was first published in the National Vulnerability Database on August 19, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66794 actively exploited?
CVE-2026-66794 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 65.1% of all scored CVEs.
What is the CVSS score of CVE-2026-66794?
CVE-2026-66794 has a CVSS v3 base score of 9.3 (NVD).
How do I remediate CVE-2026-66794?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66794, 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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