Denied Host Validation Bypass in Zitadel Actions

Zitadel is open-source identity infrastructure software. Versions prior to 2.64.1, 2.63.6, 2.62.8, 2.61.4, 2.60.4, 2.59.5, and 2.58.7 have a flaw in the URL validation mechanism of Zitadel actions allows bypassing restrictions intended to block requests to localhost (127.0.0.1). The isHostBlocked check, designed to prevent such requests, can be circumvented by creating a DNS record that resolves to 127.0.0.1. This enables actions to send requests to localhost despite the intended security measures. This vulnerability potentially allows unauthorized access to unsecured internal endpoints, which may contain sensitive information or functionalities. Versions 2.64.1, 2.63.6, 2.62.8, 2.61.4, 2.60.4, 2.59.5, and 2.58.7 contain a patch. No known workarounds are available.