CVE-2026-34046
Langflow: Authenticated Users Can Read, Modify, and Delete Any Flow via Missing Ownership Check
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | langflow | <= 1.5.0 | 1.5.1 |
| pip | langflow-base | <= 0.5.0 | 0.5.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Langflow | Langflow | before 1.5.0 Version 1.5.0 |
| Langflow | Langflow-Base | before 0.5.1 |