A vulnerability has been identified within Rancher that can be exploited in narrow circumstances through a man-in-the-middle (MITM) attack. An attacker would need to have control of an expired domain or execute a DNS spoofing/hijacking attack against the domain to exploit this vulnerability. The targeted domain is the one used as the Rancher URL.
https://github.com/rancher/rancher/security/advisories/GHSA-h4h5-9833-v2p4