CVE-2026-34046: Langflow

High severity, CVSS 8.8. EPSS: 0.7% chance of exploitation in the next 30 days.

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 products

• Langflow Langflow: before 1.5.0 (fixed in 1.5.0); version 1.5.0 only
• Langflow Langflow-Base: before 0.5.1 (fixed in 0.5.1)

Published 2026-03-27. Last modified 2026-06-17.