CVE-2026-66787

HIGHPre-NVD 5.48.7▲
EchelonGraph scoreMEDIUM confidence

Score 8.7 from GitHub Security Advisory (severity: HIGH) published 2026-08-20. a secondary CVSS source baseline 5.4; sources differ by 3.3.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
8.7EG
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

A fix is available — apply it.

A flaw was found in the lighthouse component of Red Hat Advanced Cluster Management for Kubernetes. This vulnerability stems from insufficient validation of advertised IP addresses within EndpointSlice objects. A compromised spoke cluster can exploit this by creating EndpointSlices with attacker-controlled IP addresses, causing other clusters' lighthouse DNS to redirect legitimate service traffic to malicious endpoints. This enables a remote attacker to conduct transparent Man-in-the-Middle (MITM) attacks on cross-cluster service communications, potentially leading to unauthorized information disclosure and data manipulation.

CVSS v3
5.4
EG Score
8.7(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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
Severity87% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
15%
KEV
Not listed

Published

August 20, 2026

Last Modified

September 3, 2026

Advisory Details (2)

Auto-updated Aug 20, 2026
Patch available. Sources: redhat.
redhat

2507532 – (CVE-2026-66787) CVE-2026-66787 lighthouse: lighthouse: cross-cluster DNS spoofing via unvalidated EndpointSlice and ServiceImport IPs

https://bugzilla.redhat.com/show_bug.cgi?id=2507532
redhat Patch Available

CVE-2026-66787 - 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-2026-66787

Vendor Advisories for CVE-2026-66787(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrhacm2/submariner-rhel9-operator:17880734812026-09-03redhat

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(2)

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

Data Freshness Timeline

(refreshed 40× in last 7d / 161× 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 161 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-66787?
CVE-2026-66787 is a high vulnerability published on August 20, 2026. A flaw was found in the lighthouse component of Red Hat Advanced Cluster Management for Kubernetes. This vulnerability stems from insufficient validation of advertised IP addresses within EndpointSlice objects. A compromised spoke cluster can exploit this by creating EndpointSlices with…
When was CVE-2026-66787 disclosed?
CVE-2026-66787 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on September 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66787 actively exploited?
CVE-2026-66787 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 84.6% of all scored CVEs.
What is the CVSS score of CVE-2026-66787?
CVE-2026-66787 has a CVSS v3 base score of 5.4 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 8.7.
How do I remediate CVE-2026-66787?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66787, 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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