CVE-2026-34046

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.5.1, the _read_flow helper in src/backend/base/langflow/api/v1/flows.py branched on the AUTO_LOGIN setting to decide whether to filter by user_id. When AUTO_LOGIN was False (i.e., authentication was enabled), neither branch enforced an ownership check — the query returned any flow matching the given UUID regardless of who owned it. This allowed any authenticated user to read any other user's flow, including embedded plaintext API keys; modify the logic of another user's AI agents, and/or delete flows belonging to other users. The vulnerability was introduced by the conditional logic that was meant to accommodate public/example flows (those with user_id = NULL) under auto-login mode, but inadvertently left the authenticated path without an ownership filter. The fix in version 1.5.1 removes the AUTO_LOGIN conditional entirely and unconditionally scopes the query to the requesting user.