A vulnerability has been identified in Steve where by default it was using an insecure option that did not validate the certificate presented by the remote server while performing a TLS connection. This could allow the execution of a man-in-the-middle (MitM) attack against services using Steve.
For example, Rancher relies on Steve as a dependency for its user interface (UI) to proxy requests to Kubernetes clusters. Users who have the permission to create a service in Rancher’s local cluster can take over Rancher’s UI and display their own UI to gather sensitive information. This is only possible when the setting ui-offline-preferred
is manually set to remote
(by default Rancher sets it to dynamic
). This enables further attacks such as cross-site scripting (XSS), or tampering the UI to collect passwords from other users etc.
Please consult the associated MITRE ATT&CK - Technique - Adversary-in-the-Middle for further information about this category of attack.
Patched versions of Steve include releases v0.2.1
, v0.3.3
, v0.4.4
and v0.5.13
.
This vulnerability is addressed by changing Steve to always verify a server’s certificate based on Go’s TLS settings.
If you can't upgrade to a fixed version, please make sure that you are only using Steve to connect to trusted servers.
If you have any questions or comments about this advisory: - Reach out to the SUSE Rancher Security team for security related inquiries. - Open an issue in the Rancher repository. - Verify with our support matrix and product support lifecycle.
{ "nvd_published_at": null, "cwe_ids": [ "CWE-295" ], "severity": "HIGH", "github_reviewed": true, "github_reviewed_at": "2025-04-25T15:12:44Z" }