CVE-2026-66785

Submariner: submariner: missing validation of remote endpoint subnets and clusterid enables cross-cluster traffic hijack

HIGH
8.7
CVSS Score
Published: August 20, 2026 at 06:15 PM UTC
Updated: October 19, 2026 at 06:17 PM UTC
1 product affected across 1 vendorAdvanced Cluster Management for Kubernetes

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Severity
HIGH8.7
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

A flaw was found in Submariner. This vulnerability allows a malicious cluster (spoke) to redirect network traffic from other connected clusters (peer clusters) by publishing a specially crafted network endpoint. The system fails to properly validate the network subnets provided by the malicious cluster, enabling it to declare arbitrary network ranges. Consequently, all network traffic intended for these arbitrary ranges from peer clusters will be rerouted through the attacker's tunnel, potentially leading to unauthorized information disclosure or network disruption.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions2
Vendor states this is fixed in 1788023916 (unaffected)
Vendor states this is fixed in 1788023940 (unaffected)
Vendor states this is fixed in 1788043961 (unaffected)
Vendor states this is fixed in 1788043964 (unaffected)
Vendor states this is fixed in 1788043970 (unaffected)
Vendor states this is fixed in 1788073481 (unaffected)
Vendor states this is fixed in 1788105072 (unaffected)
Vendor states this is fixed in 1790670231 (unaffected)
Vendor states this is fixed in 1790670233 (unaffected)
Vendor states this is fixed in 1790670243 (unaffected)
Vendor states this is fixed in 1790670254 (unaffected)
Vendor states this is fixed in 1790670439 (unaffected)
Vendor states this is fixed in 1790670508 (unaffected)
Vendor states this is fixed in 1790670912 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

VDB Entryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-66785
Issue Trackingx_refsource_REDHAT
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2507530
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:63016
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:85227

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.7HIGHredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-20CWE-732CWE-345

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