Critical [CVE-2026-66786] ipsec.conf stanza injection via remote-supplied CableName and Subnets
This critical-severity Red Hat Linux advisory covers CVE-2026-66786.
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Summary
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.
Red Hat rates this flaw as Moderate severity rather than Important because exploitation requires two non-default configurations that must both be explicitly enabled by an administrator. The vulnerable code path exists only in Submariner's certificate-based IPsec authentication mode, which is disabled by default (`IPSecCertAuthMode` defaults to `false`).
This mode is designed specifically for integration with OVN-Kubernetes IPsec, which is itself an optional intra-cluster encryption feature that is also disabled by default.
The standard Submariner deployment, including multi-cloud and cross-datacenter configurations managed through Red Hat Advanced Cluster Management, uses pre-shared key (PSK) authentication, which establishes IPsec tunnels through a structurally different code path (`ipsec whack` command-line arguments via Go's `exec.
Command`) that is not susceptible to this injection.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 47 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 47 minutes ago·verify at source
Mitigation checklist
- If Submariner certificate-based IPsec authentication mode is enabled (`IPSecCertAuthMode: true` in the SubmarinerConfig), administrators can mitigate this flaw by switching to the default pre-shared key (PSK) authentication mode. Set `IPSecCertAuthMode: false` (or remove the field to use its default value) in the SubmarinerConfig CR and redeploy the Submariner gateway pods. PSK mode provides equivalent inter-cluster IPsec tunnel encryption and is not affected by this vulnerability. Note that disabling cert-auth mode means Submariner will no longer integrate with OVN IPsec's certificate infrastructure and will manage its own PSK-based authentication independently.
Official advisory · high-confidence parse· fetched 47 minutes ago·verify at source
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