Cline is safe to run, but because it works as an autonomous agent that edits files and executes commands across a whole task, the same predictable weaknesses appear quickly and in more than one place. The pattern is the same as any capable assistant: it inlines a key to unblock an integration, and it wires up endpoints without the server-side authorization that is not required for the feature to run. Review its diffs for secrets and missing auth before you accept them.
The risks that actually matter
Secrets inlined during multi-step tasks
Working through a task autonomously, Cline may place a key directly in code at the moment an integration needs it, and that value ends up in the repo unless you catch it in the diff.
Commands run without review
In auto-approve mode, Cline can run shell commands that write secrets to files or history, or fetch and execute code, before you have a chance to inspect them.
Missing server-side authorization
Endpoints it generates often trust the caller, leaving data readable or writable by anyone who calls the route directly.
How to secure a Cline app
- Review Cline's diffs before accepting; do not leave broad auto-approve on for shell commands.
- Reject any change that writes a literal key; require environment variables instead.
- Add server-side auth checks to generated endpoints.
- Scan the result for hardcoded secrets and missing auth once the task completes.