CVE-2025-23389 is an improper access control vulnerability classified under CWE-284, discovered in SUSE Rancher, a popular container management platform. The flaw exists in the SAML authentication mechanism during the first login, where a local user with low privileges can impersonate other identities. This vulnerability affects Rancher versions from 2.8.0 up to but not including 2.8.13, 2.9.0 up to but not including 2.9.7, and 2.10.0 up to but not including 2.10.3. The issue arises because the system does not properly enforce access controls when processing SAML assertions on initial login, allowing an attacker to bypass identity verification and assume the identity of other users. The CVSS v3.1 base score is 8.4, indicating high severity, with attack vector as network, attack complexity high, privileges required low, no user interaction, and scope changed. The vulnerability impacts confidentiality and integrity significantly, with limited impact on availability. No public exploits have been reported yet, but the potential for privilege escalation and unauthorized access within container orchestration environments is substantial. The vulnerability was published on April 11, 2025, and SUSE has not yet provided patch links, indicating that mitigation may currently rely on workarounds or configuration changes.

The vulnerability allows a local attacker to impersonate other users by exploiting improper access control in the SAML authentication process, potentially leading to unauthorized access to sensitive data and administrative functions within Rancher-managed environments. This can result in privilege escalation, data breaches, and manipulation of container orchestration workflows. Given Rancher's widespread use in managing Kubernetes clusters and containerized applications, exploitation could disrupt critical infrastructure, cloud services, and enterprise applications. The confidentiality and integrity of systems are at high risk, as attackers could assume identities of privileged users. Availability impact is low but could increase if attackers leverage impersonation to disrupt services. Organizations relying on Rancher for container management, especially those in regulated industries or with sensitive workloads, face significant operational and compliance risks.

Organizations should immediately identify and inventory affected Rancher versions in their environments. Since no patches are currently linked, administrators should monitor SUSE advisories for updates and apply patches as soon as they become available. In the interim, restrict local access to Rancher servers to trusted personnel only, as exploitation requires local user privileges. Review and harden SAML authentication configurations, including validating assertion sources and enforcing strict identity verification policies. Implement multi-factor authentication (MFA) where possible to reduce the risk of impersonation. Monitor Rancher logs for unusual authentication events or identity changes. Consider isolating Rancher management interfaces from general user networks and applying network segmentation to limit exposure. Conduct regular security audits and penetration tests focusing on authentication mechanisms. Finally, educate administrators about this vulnerability and the importance of timely updates.