Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. When using `--auth-mode=client`, Archived Workflows can be retrieved with a fake or spoofed token via the GET Workflow endpoint: `/api/v1/workflows/{namespace}/{name}` or when using `--auth-mode=sso`, all Archived Workflows can be retrieved with a valid token via the GET Workflow endpoint: `/api/v1/workflows/{namespace}/{name}`. No authentication is performed by the Server itself on `client` tokens. Authentication & authorization is instead delegated to the k8s API server. However, the Workflow Archive does not interact with k8s, and so any token that looks valid will be considered authenticated, even if it is not a k8s token or even if the token has no RBAC for Argo. To handle the lack of pass-through k8s authN/authZ, the Workflow Archive specifically does the equivalent of a `kubectl auth can-i` check for respective methods. In 3.5.7 and 3.5.8, the auth check was accident…

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. Due to a race condition in a global variable in 3.6.0-rc1, the argo workflows controller can be made to crash on-command by any user with access to execute a workflow. This vulnerability is fixed in 3.6.0-rc2.

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. In affected versions an attacker can create a workflow which produces a HTML artifact containing an HTML file that contains a script which uses XHR calls to interact with the Argo Server API. The attacker emails the deep-link to the artifact to their victim. The victim opens the link, the script starts running. As the script has access to the Argo Server API (as the victim), so may read information about the victim’s workflows, or create and delete workflows. Note the attacker must be an insider: they must have access to the same cluster as the victim and must already be able to run their own workflows. The attacker must have an understanding of the victim’s system. We have seen no evidence of this in the wild. We urge all users to upgrade to the fixed versions.

In Argo Workflows through 3.1.3, if EXPRESSION_TEMPLATES is enabled and untrusted users are allowed to specify input parameters when running workflows, an attacker may be able to disrupt a workflow because expression template output is evaluated.