CVE-2026-10547 is an improper access control vulnerability (CWE-284) in IBM Langflow OSS versions 1.0.0 through 1.10.3. The issue exists in the deprecated POST /api/v1/build/{flow_id}/vertices endpoint, which does not properly validate ownership of the flow. As a result, an authenticated user can inject arbitrary graph data into the shared cache of any flow, leading to potential cross-user cache pollution, unauthorized execution of workflows, or denial of service conditions. No official patch or remediation guidance is currently provided by the vendor, and no known exploits are reported in the wild.

An attacker with authenticated access can manipulate the shared cache by injecting arbitrary graph data for any flow, which may cause other users' workflows to execute unauthorized actions or disrupt service availability. This can lead to denial of service or unauthorized workflow execution, impacting the integrity and availability of the affected system.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict access to the deprecated POST /api/v1/build/{flow_id}/vertices endpoint and monitor for unusual activity related to workflow execution. Avoid using deprecated endpoints if possible.