EUVD-2026-33275
GHSA-76ww-43j5-78x5
Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Primary rating from NVD.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Lifecycle Timeline
3DescriptionNVD
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.
AnalysisAI
Server-side request forgery in Red Hat OpenShift Container Platform 4's Router component allows authenticated users with EndpointSlice write permissions to coerce the router into proxying requests to cloud provider instance metadata endpoints (e.g., 169.254.169.254), exposing instance credentials and sensitive metadata. The flaw bypasses prior IP-address-based validation by abusing FQDN-backed EndpointSlices that resolve to metadata services. No public exploit identified at time of analysis, and the issue is not present on CISA KEV.
Technical ContextAI
OpenShift Router is the HAProxy-based ingress component in Red Hat OpenShift Container Platform 4, responsible for routing external traffic to in-cluster Services. Services in Kubernetes can be backed by EndpointSlice objects, which may specify endpoints by IP or by FQDN; the router resolves these endpoints to forward traffic. This vulnerability is a classic CWE-918 Server-Side Request Forgery: prior hardening blocked link-local and metadata IPs (e.g., 169.254.169.254 on AWS/Azure/GCP) at the IP layer, but the FQDN code path performs DNS resolution at request time, allowing an attacker-controlled hostname to resolve to those same restricted addresses and bypass the validation. Cloud instance metadata services typically expose IAM credentials, user-data, and configuration that can be pivoted into broader cloud account compromise.
RemediationAI
Patch available per vendor advisory: apply the OpenShift Container Platform 4 update referenced in https://access.redhat.com/security/cve/CVE-2026-42965 for your supported channel, and track the Bugzilla entry https://bugzilla.redhat.com/show_bug.cgi?id=2483184 for the exact z-stream fix versions. Until patched, restrict EndpointSlice and Services write RBAC to trusted administrators via cluster role audits (revoke endpointslices/endpoints create/update from project-editor and custom roles where feasible), accepting that this may break workflows requiring user-managed external service definitions. On AWS, enforce IMDSv2 with hop-limit 1 on router nodes to render token-less metadata requests from HAProxy unusable; on Azure/GCP, apply equivalent metadata-access hardening or use a node-level egress firewall to block 169.254.169.254 and fd00:ec2::254 from router pods, noting that this may break legitimate node-bootstrap or cloud-controller flows if misapplied. Add an admission policy (e.g., Kyverno/OPA Gatekeeper) to reject EndpointSlice objects whose addresses or FQDNs resolve to link-local or cloud metadata ranges as a defense-in-depth control.
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Same weakness CWE-918 – Server-Side Request Forgery (SSRF)
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