Ubuntu Completes Migration of Core Utilities to Rust-Based Implementation

Ubuntu has successfully completed the migration of its core utilities from GNU Core Utilities to the uutils project, which reimplements these tools in Rust. The final three utilities, cp, mv, and rm, have been replaced with Rust-based versions, completing a process that began with Ubuntu 25.10, which was the first release to ship uutils coreutils as the default. Earlier releases had already migrated other utilities like ls, cat, chmod, and du. Canonical, the company behind Ubuntu, started the ‘Rust-ification’ initiative last year, aiming to modernize the codebase and improve security. The migration faced challenges, particularly with cp, mv, and rm, which were delayed due to TOCTOU (Time of Check to Time of Use) security issues identified during audits commissioned by Canonical. These audits, conducted by Zellic between December 2025 and March 2026, uncovered 113 issues, 44 of which were assigned CVEs. Canonical reported that most of these issues have been resolved. The uutils project aims to be a drop-in replacement for GNU tools, maintaining compatibility while offering memory safety benefits through Rust. Users who prefer the GNU version can still install the coreutils-from-gnu package. The migration process has not been without setbacks; for instance, uutils cp was temporarily removed from the archive after breaking live image builds but was quickly fixed and reintegrated. The Rust implementation is licensed under MIT, unlike the GPLv3 license of GNU Core Utilities, potentially encouraging wider adoption across different platforms. The project has also benefited GNU Core Utilities by uncovering bugs through extensive testing. Despite some concerns about compatibility and security issues, Canonical maintains that the Rust-based implementation is a significant step toward modernizing Ubuntu’s core infrastructure.