CVE-2026-66786: Submariner: submariner: ipsec.conf stanza injection via remote-supplied cablename and subnets

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-02 · updated 2026-10-19
Weakness: CWE-94

Description

A flaw was found in submariner. In cert-auth mode, the connection configuration is built using free-form strings from the Custom Resource Definition (CRD) without proper validation. A malicious cluster can exploit this by publishing a CableName that includes newlines and ipsec.conf directives. This allows an attacker to inject arbitrary configuration parameters or execute commands through leftupdown hooks, leading to remote code execution as root on the gateway node.

Affected products

Red Hat Advanced Cluster Management for Kubernetes 2: all versions
Red Hat Advanced Cluster Management for Kubernetes 2.16: all versions — fixed in 1790670231, 1790670233, 1790670243, 1790670254, 1790670439, 1790670508
Red Hat Advanced Cluster Management for Kubernetes 2.17: all versions — fixed in 1788023916, 1788023940, 1788043961, 1788043964, 1788043970, 1788073481

How to fix

Upgrade to a fixed version: Red Hat Advanced Cluster Management for Kubernetes 2.16 1790670231, 1790670233, 1790670243, 1790670254; Red Hat Advanced Cluster Management for Kubernetes 2.17 1788023916, 1788023940, 1788043961, 1788043964. Check the vendor advisory for mitigations.

References

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