Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes. Due to the improper URL protocols filtering of links specified in the `link.argocd.argoproj.io` annotations in the application summary component, an attacker can achieve cross-site scripting with elevated permissions. All unpatched versions of Argo CD starting with v1.0.0 are vulnerable to a cross-site scripting (XSS) bug allowing a malicious user to inject a javascript: link in the UI. When clicked by a victim user, the script will execute with the victim's permissions (up to and including admin). This vulnerability allows an attacker to perform arbitrary actions on behalf of the victim via the API, such as creating, modifying, and deleting Kubernetes resources. A patch for this vulnerability has been released in Argo CD versions v2.10.3 v2.9.8, and v2.8.12. There are no completely-safe workarounds besides upgrading. The safest alternative, if upgrading is not possible, would be to create a Kubernetes admission controller to reject any resources with an annotation starting with link.argocd.argoproj.io or reject the resource if the value use an improper URL protocol. This validation will need to be applied in all clusters managed by ArgoCD.
Argo CD improperly filters URL protocols in links specified in `link.argocd.argoproj.io` annotations displayed in the application summary component. An attacker can place a value in this annotation containing a `javascript:` scheme, which is not blocked by validation. When a logged-in user clicks the crafted link in the interface, the browser executes the embedded JavaScript code in the context of the victim's session. This code can use the full permissions of the victim, including administrative permissions, to communicate with the Argo CD API.
An attacker can perform arbitrary operations on Kubernetes resources on behalf of the victim through the Argo CD API, including creating, modifying, and deleting resources across all clusters managed by Argo CD.
Argo CD should be updated to version v2.10.3, v2.9.8, or v2.8.12. If updating is not possible, as a temporary workaround, a Kubernetes admission controller should be implemented to reject resources with annotations starting with `link.argocd.argoproj.io` or containing invalid URL protocols — validation must be applied across all clusters managed by Argo CD.
All unpatched versions of Argo CD starting from v1.0.0
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:HArgoproj Argo Cd
APPArgoproj1.0.0 – 2.8.12 (excl.)2.9.0 – 2.9.8 (excl.)2.10.0 – 2.10.3 (excl.)
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