OpenShift Router Metadata Endpoint Proxy Bypass

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.

Casky was already ahead

This CVE exploits attack patterns that Casky's 312matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

CVE-2026-42965 exposes a critical vulnerability in OpenShift Router where users with EndpointSlice write permissions can redirect traffic to cloud metadata endpoints by creating Services backed by FQDN-based EndpointSlices. This bypasses IP address validation controls that previously protected cloud metadata services like AWS IMDSv1/v2, Azure IMDS, and GCP metadata endpoints. Attackers exploit this to extract instance credentials, role ARNs, temporary tokens, and other sensitive metadata without direct network access—effectively turning the router into a proxy for credential theft. Any organization running OpenShift in cloud environments is affected, particularly those with multi-tenant clusters where service account permissions are broadly distributed.

Casky's 312 matched skills detect this attack pattern by mapping to MITRE ATT&CK techniques TA0001 (Initial Access) and TA0006 (Credential Access). Claude's extended reasoning identifies suspicious behavioral patterns: EndpointSlice creation with FQDN values pointing to known metadata service ranges (169.254.x.x, metadata.google.internal, etc.), anomalous proxy traffic destined for cloud metadata endpoints, and credential material appearing in router logs or audit events. Practitioners using Casky would see findings flagged for unusual Service configurations with external FQDNs, unexpected outbound connections from the router to metadata endpoints, and correlations between EndpointSlice modifications and subsequent credential exposure events—enabling detection of both configuration-based exploitation and post-compromise credential exfiltration.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

312 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-42965.

analyzing-cloud-storage-access-patterns

cloud security · low

Run

analyzing-ios-app-security-with-objection

mobile security · low

Run

analyzing-malicious-url-with-urlscan

phishing defense · medium

Run

MITRE ATT&CK Techniques

TA0001 TA0006

Investigate the attack patterns behind CVE-2026-42965

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