CVE-2026-34046
Description
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.
How to fix
- langflow langflow1.5.0 or later
- langflow langflow-base0.5.1 or later
- langflow1.5.1 or later
- langflow-base0.5.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| langflow langflow | v < 1.5.0, 1.5.0 | 1.5.0 |
| langflow langflow-base | v < 0.5.1 | 0.5.1 |
| langflowPyPI | v < 1.5.1 | 1.5.1 |
| langflow-basePyPI | v < 0.5.1 | 0.5.1 |
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