CVE-2026-33760 describes an authorization bypass vulnerability in langflow-ai's langflow product affecting versions before 1.9.0. The /api/v1/monitor router exposes seven endpoints that perform read, write, rename, and delete operations on user-owned resources without verifying that the authenticated user owns the targeted resource. This allows any authenticated user to access or modify another user's data by supplying the target resource ID or flow_id. The vulnerability is categorized as CWE-639 (Authorization Bypass Through User-Controlled Key). The source code shows inconsistent application of ownership checks, as one endpoint correctly implements this check. The issue is resolved in version 1.9.0.

An attacker with valid authentication credentials can read, modify, rename, or permanently delete resources belonging to other users. This compromises confidentiality, integrity, and availability of user data within the affected system. The CVSS v3.1 base score is 8.8 (high), reflecting network attack vector, low attack complexity, required privileges, no user interaction, and high impact on confidentiality, integrity, and availability.

Upgrade langflow to version 1.9.0 or later, where this authorization bypass vulnerability is fixed. No other mitigation or temporary workaround is indicated in the available data.