Bug 2483184 (CVE-2026-42965)

Summary: CVE-2026-42965 openshift/router: openshift/router: cloud metadata SSRF via FQDN-typed EndpointSlice bypasses destination validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the OpenShift Router. A user with EndpointSlice write access can exploit this vulnerability by creating a Service backed by an FQDN (Fully Qualified Domain Name) EndpointSlice that resolves to a cloud metadata endpoint. This allows the router to proxy requests to the cloud metadata endpoint, leading to the disclosure of instance credentials and other sensitive metadata. This bypasses previous security measures for validating IP addresses.
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Description OSIDB Bzimport 2026-05-29 09:43:28 UTC 
The OpenShift Router does not validate backend destinations resolved from FQDN-typed EndpointSlices. A user with EndpointSlice write access can create a Service backed by an FQDN EndpointSlice pointing to a hostname that resolves to 169.254.169.254 (e.g. 169-254-169-254.nip.io), then create a Route targeting that Service. The router proxies requests to the cloud metadata endpoint, allowing the attacker to retrieve instance credentials and other sensitive metadata. This bypasses the fix for CVE-2021-25737, which only validates IPv4/IPv6 addresses via ValidateEndpointIP() but not FQDN endpoints. IMDSv2 does not mitigate this because HAProxy runs as a hostNetwork process at Layer 7 and can perform the PUT/GET token exchange. This attack requires the IngressController to use HostNetwork endpoint publishing (default on bare metal/UPI, not on cloud providers).