The package github.com/argoproj/argo-cd/cmd before 1.7.13, from 1.8.0 and before 1.8.6 are vulnerable to Cross-site Scripting (XSS) the SSO provider connected to Argo CD would have to send back a malicious error message containing JavaScript to the user.
As of v1.5.0, the Argo web interface authentication system issued immutable tokens. Authentication tokens, once issued, were usable forever without expiration—there was no refresh or forced re-authentication.
As of v1.5.0, the Argo API does not implement anti-automation measures such as rate limiting, account lockouts, or other anti-bruteforce measures. Attackers can submit an unlimited number of authentication attempts without consequence.
As of v1.5.0, the default admin password is set to the argocd-server pod name. For insiders with access to the cluster or logs, this issue could be abused for privilege escalation, as Argo has privileged roles. A malicious insider is the most realistic threat, but pod names are not meant to be kept secret and could wind up just about anywhere.