CVE-2026-42965

Vulnerability

A flaw in the OpenShift Router allows a user with EndpointSlice write access to create a Service backed by a Fully Qualified Domain Name (FQDN) EndpointSlice that resolves to a cloud metadata endpoint such as 169.254.169.254. The router fails to validate backend destinations resolved from FQDN-typed EndpointSlice entries, thereby bypassing the IP-address validation introduced for CVE-2021-25737. The attack requires that the IngressController uses HostNetwork endpoint publishing (default on bare metal and User Provisioned Infrastructure, but not on cloud provider-integrated installations). [1][2]

Exploitation

An attacker with EndpointSlice write access can create a Service backed by an FQDN EndpointSlice pointing to a hostname that resolves to the cloud metadata IP (e.g., 169-254-169-254.nip.io). The attacker then creates a Route targeting that Service. The OpenShift Router proxies requests to the cloud metadata endpoint. The attacker does not need initial network access to the metadata service because HAProxy, running as a hostNetwork process at Layer 7, performs the HTTP request. Even IMDSv2 is not a mitigation since HAProxy can complete the required PUT/GET token exchange. [2]

Impact

Successful exploitation results in disclosure of cloud instance credentials and other sensitive metadata from the cloud metadata endpoint. This represents a confidentiality breach; the attacker can obtain information such as temporary access tokens, SSH keys, or other secrets that may enable further compromise of the cloud environment. [1][2]

Mitigation

Red Hat has not yet released a fixed version; the vulnerability was published on 2026-05-29 and is currently under investigation. As a workaround, ensure that the IngressController does not use HostNetwork endpoint publishing where possible, or restrict EndpointSlice write access to trusted users only. The issue is tracked in Red Hat Bugzilla [2] and may be updated with a patch in a future OpenShift release. [2]