The clickjacking vulnerability in ZenML stemmed from the absence of security headers (X-Frame-Options, Content-Security-Policy) in HTTP responses, not from specific vulnerable functions in the codebase. The root cause was the lack of middleware or configuration to enforce these headers. The fix introduced a new middleware function (set_secure_headers in src/zenml/zen_server/zen_server_api.py) to add the headers, which was missing in prior versions. Since the vulnerability arose from the omission of this security mechanism rather than a flawed function, no specific pre-existing functions in ZenML's code directly caused the issue. The patched version addressed this by adding the missing security header logic.