pnpm: pacquet before 12.0.0-alpha.5 Path Traversal via lockfile alias

pacquet, the Rust package-manager component shipped in the pnpm npm package versions >=12.0.0-alpha.0 and <12.0.0-alpha.5, does not validate dependency alias/name paths taken from a lockfile before using them in install-time filesystem joins. When a user installs a project with an attacker-supplied lockfile using --trust-lockfile or a frozen lockfile, alias entries containing path traversal segments (for example '../../escaped-link') are used when creating dependency and package links, bin destinations, hoisted entries, and virtual-store slots, allowing symlinks and directories to be created outside the intended project and node_modules boundary. Version 12.0.0-alpha.5 validates dependency names and every virtual-store slot path with a shared safe-join containment helper before any filesystem materialization, rejecting traversal, absolute, platform-specific, and reserved names with ERR_PNPM_INVALID_DEPENDENCY_NAME.