The RustSec monorepo is a multi-crate workspace that provides the official security audit toolchain for the Rust ecosystem. Its flagship product is `cargo-audit`, a CLI subcommand for Cargo that scans `Cargo.lock` files against the RustSec Advisory Database to detect known vulnerabilities, unmaintained or unsound crates, and yanked packages. The workspace also includes the `rustsec` core library for managing the advisory database (fetched via git, indexed, and queried), `cargo-lock` for parsing and manipulating Cargo.lock files (supporting V1 through V4 format), `cvss` for parsing and scoring CVSS vectors (v2.0, v3.x, v4.0), `platforms` for programmatic access to Rust target triples, and `admin` for maintaining the advisory database and generating the rustsec.org website. Although primarily an application and library toolset, the repository has data-oriented aspects: the advisory database is a curated set of Markdown files with TOML front matter, and `platforms` is auto-generated from rustc target information. The architecture is modular, with each crate independently usable and well-tested, and CI pipelines ensure cross-platform releases and static analysis.