A Go module is a versioned package unit in the Go ecosystem. It groups source code, dependencies, and release metadata so other projects can import it with predictable versions. Modules are the basis of modern Go dependency management, replacing older GOPATH-based workflows with explicit version pinning and reproducible builds.
In cyber security, modules matter because they sit in the software supply chain. If a widely used module changes hands, is published with a malicious update, or loses release integrity, downstream projects can inherit the risk immediately. Attackers may target module names, tags, or dependency resolution to insert unwanted code, while defenders use checksums, private mirrors, pinned versions, and review of maintainers and release history to reduce exposure. In incidents involving trusted libraries such as fsnotify, concern often centers not only on code quality but on who can publish the next module version.