CVE-2025-54468 is a medium severity vulnerability identified in SUSE Rancher Manager versions 2.9.0 through 2.12.0. The issue involves the exposure of sensitive information due to improper handling of HTTP headers, specifically the `Impersonate-Extra-*` headers, which are sent via the `/meta/proxy` endpoint to external entities such as domains under amazonaws.com. These headers can contain sensitive and identifiable information, including email addresses, which should not be exposed to unauthorized external parties. The vulnerability falls under CWE-200, indicating an exposure of sensitive information to unauthorized actors. The CVSS v3.1 base score is 4.7, reflecting a medium severity level. The vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N) indicates that the vulnerability can be exploited remotely over the network without privileges but requires user interaction. The scope is changed (S:C), meaning the vulnerability affects components beyond the initially vulnerable component. The impact is limited to confidentiality loss, with no integrity or availability impact. No known exploits are currently reported in the wild, and no patches have been linked yet. This vulnerability is significant because Rancher Manager is widely used for Kubernetes cluster management and orchestration, and leaking user-identifiable information to external cloud domains could lead to privacy violations, targeted phishing, or reconnaissance by attackers. The exposure occurs through a proxy endpoint that forwards headers externally, which suggests a misconfiguration or design flaw in how Rancher handles proxy requests and header forwarding.

For European organizations, the exposure of sensitive user information such as email addresses can have several adverse effects. Firstly, it can lead to privacy breaches violating GDPR regulations, potentially resulting in legal penalties and reputational damage. Secondly, leaked information can be used by threat actors to craft targeted phishing campaigns or social engineering attacks, increasing the risk of credential compromise or lateral movement within networks. Since Rancher is commonly used in cloud-native environments and DevOps pipelines, attackers gaining reconnaissance information can better tailor attacks against critical infrastructure or intellectual property. Although the vulnerability does not directly allow system compromise or denial of service, the confidentiality loss can be a stepping stone for more severe attacks. The fact that the headers are sent to external domains like amazonaws.com raises concerns about data exfiltration to third-party cloud services, which may be outside the control of the affected organization. This is particularly sensitive for organizations handling regulated or confidential data. The requirement for user interaction (UI:R) implies that exploitation may depend on a user triggering the vulnerable request, which somewhat limits the attack surface but does not eliminate risk, especially in automated or scripted environments.

To mitigate this vulnerability, European organizations using affected Rancher versions should: 1) Immediately review and restrict the use of the `/meta/proxy` endpoint to trusted internal destinations only, ensuring that no sensitive headers are forwarded to external or untrusted domains. 2) Implement strict network egress filtering to prevent unauthorized outbound connections from Rancher Manager to external cloud domains unless explicitly required and verified. 3) Audit and sanitize HTTP headers, particularly `Impersonate-Extra-*` headers, to ensure they do not contain sensitive information before forwarding or proxying requests. 4) Monitor Rancher logs and network traffic for unusual or unexpected outbound requests containing sensitive headers. 5) Educate users and administrators about the risk of user interaction-based exploitation and enforce least privilege principles to minimize exposure. 6) Stay alert for official patches or updates from SUSE and apply them promptly once available. 7) Consider deploying Web Application Firewalls (WAFs) or API gateways that can detect and block suspicious header forwarding or proxy misuse. 8) Review and update incident response plans to include scenarios involving sensitive data exposure through management platforms like Rancher.