systeminformation is a System and OS information library for node.js. Prior to 5.33.13, networkStats(ifaces) in lib/network.js on FreeBSD, OpenBSD, and NetBSD stores per-interface data in the plain-object _network cache and indexes it with the sanitized caller-controlled interface name. Passing proto causes the inherited Object.prototype value to be used instead of creating an own cache entry, so calcNetworkSpeed() writes rx_bytes, tx_bytes, rx_sec, tx_sec, ms, last_ms, and operstate onto Object.prototype. The polluted property names are fixed and their values come from interface statistics, but inherited-name collisions and enumerable keys can corrupt application branching, serialization, configuration merging, validation, or lookup behavior. This issue is fixed in version 5.33.13.