CVE-2026-33760 is an authorization bypass vulnerability (CWE-639) in langflow-ai's langflow product affecting versions prior to 1.9.0. The /api/v1/monitor router exposes seven endpoints that perform read, write, and delete operations on user-owned resources without verifying that the authenticated user owns the targeted resource. This allows any authenticated user to manipulate other users' data by supplying the resource ID or flow_id. The vulnerability is due to inconsistent application of ownership checks, as one endpoint in the same source file correctly implements this check. The vulnerability is fixed 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 langflow instances. The CVSS v3.1 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 documented. Since this is not a cloud service, remediation depends on applying the official fix.