Warning: Security Trap with Rails Global IDs in AI Agent Applications

This article reveals a critical security vulnerability in the Rails framework’s Global ID (GID) system when integrating with Large Language Model (LLM) applications. The author discovered while building a personal accounting and invoicing tool with RubyLLM that when an LLM incorrectly generates a GID containing a UUID, Rails extracts the numeric sequence from the UUID and incorrectly locates records in the database. This occurs because Rails’ find method attempts to extract numbers from strings as IDs, causing GIDs like ‘gid://moneaker/Invoice/22ecb3fd-5e25-462c-ad2b-cafed9435d16’ to be incorrectly parsed as invoice record with ID 22. This discovery serves as an important warning for developers integrating LLMs with traditional database applications, reminding us to strengthen GID validation and authorization checks to avoid potential data security risks.