CVE-2026-17633: Authenticated RCE Flaw Found in Langflow OSS Versions Up to 1.10.3

A high-severity remote code execution vulnerability, tracked as CVE-2026-17633 with a CVSS score of 8.5, has been disclosed in Langflow OSS versions 1.0.0 through 1.10.3. The flaw exists in the POST /api/v1/custom_component endpoint, which allows authenticated users to submit arbitrary Python code when the LANGFLOW_ALLOW_CUSTOM_COMPONENTS setting is enabled. The endpoint's security check only verifies whether a user has permission to create custom components, but never inspects the content of the submitted code for malicious instructions. An attacker can exploit this by placing a system command inside a class body, causing it to execute at class-definition time via an unchecked exec() call in the platform's component-building logic. The vulnerability is classified under CWE-94 (Improper Control of Code Generation) and requires no special encoding or bypass techniques to exploit successfully.