The Apollo Router Core is a configurable, high-performance graph router written in Rust to run a federated supergraph that uses Apollo Federation 2. Prior to 1.61.2 and 2.1.1, the operation limits plugin uses unsigned 32-bit integers to track limit counters (e.g. for a query's height). If a counter exceeded the maximum value for this data type (4,294,967,295), it wrapped around to 0, unintentionally allowing queries to bypass configured thresholds. This could occur for large queries if the payload limit were sufficiently increased, but could also occur for small queries with deeply nested and reused named fragments. This has been remediated in apollo-router versions 1.61.2 and 2.1.1.

Apollo Router Operation Limits Vulnerable to Bypass via Integer Overflow