Executive brief
Prefect, a workflow orchestration platform, contains a security flaw that allows unauthorized users to bypass authentication. By naming resources like variables or deployments with specific suffixes such as 'health' or 'ready', an attacker can access them without a password. This could lead to the theft of sensitive business data, including API keys and database credentials stored within the system.
Technical details
An authentication bypass vulnerability exists in Prefect's server middleware due to improper path validation for health check exemptions. The middleware uses a suffix-based check (endswith) that exempts any URL ending in 'health' or 'ready' from authentication. An unauthenticated remote attacker can exploit this by creating or accessing resources (such as Variables, Flows, or Deployments) whose names end with these strings. Successful exploitation allows unauthorized access to sensitive data stored in Prefect Variables, including credentials and API keys. The issue is addressed in version 3.6.22.dev7 by tightening the path matching logic.
Affected products
- PrefectHQ Prefect < 3.6.22.dev7
Timeline
- 2026-06-02: disclosed
- 2026-06-02: advisory
- 2026-07-09: patched