Pipecat: Path Traversal in Pipecat Runner `/files` Endpoint — Arbitrary File Read via `%2F`-Encoded Separator

Pipecat is an open-source Python framework for building real-time voice and multimodal conversational agents. From version 0.0.90 to before version 1.2.0, a path traversal vulnerability exists in Pipecat's development runner (src/pipecat/runner/run.py). When the runner is started with the --folder flag, it exposes a GET /files/{filename:path} download endpoint. The filename path parameter is concatenated directly onto args.folder with no containment check. Starlette normalises literal ../ sequences in URLs, but %2F-encoded slashes bypass this normalisation: the path parameter is URL-decoded after routing, so ..%2F..%2Fetc%2Fpasswd resolves to a path two levels above args.folder. An attacker with network access to the runner can read any file the pipecat process has permission to access — including SSH private keys, credentials, and system files — with a single unauthenticated HTTP request. This issue has been patched in version 1.2.0.