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: 0.4%CVSS: 5.4Exploit: None knownExposed services: Not assessed

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
8.7HIGHmedium confidence
EG Risk
39
EG Risk 39/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
26th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

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 / EcosystemFix (by version range) / 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 36× in last 7d / 163× 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 243 total refreshes for this CVE.

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

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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 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 0.4% probability of exploitation in the next 30 days (26th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66787?
CVE-2026-66787 has a CVSS base score of 5.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 8.7 (HIGH).
How do I remediate CVE-2026-66787?
A fix for CVE-2026-66787 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-66787 are linked in the Vendor Advisories panel on this page.

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