High severity · published Aug 20, 2026
CVE-2026-66785
Submariner: submariner: missing validation of remote endpoint subnets and clusterid enables cross-cluster traffic hijack
8.7
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 11% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Advanced Cluster Management for Kubernetes 2 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Advanced Cluster Management for Kubernetes 2.16 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Advanced Cluster Management for Kubernetes 2.17 · Red Hat
All versions, or not specified · source: vendor
Affected product
RH
Red Hat Advanced Cluster Management for Kubernetes 2
Red Hat
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-66785
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-66785
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:63016
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:85227
vdb-entry
https://access.redhat.com/security/cve/CVE-2026-66785
issue-tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2507530
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