CVE-2026-59206: n8n: Prototype Pollution via Workflow Credentials Leads to Unauthenticated User and Project Enumeration

An authenticated user with the default workflow:create permission could pollute Object.prototype through a crafted workflow saved, updated, or imported via the workflow API. This can be leveraged to bypass authentication, allowing unauthenticated requests to be treated as a privileged user and exposing endpoints such as the user and project listings. As a result, every account’s personal data (email, role, MFA status) and all projects on the instance may be disclosed to unauthenticated callers. The pollution can also corrupt global state, making parts of the instance unresponsive until restarted.