Mold 3.0 is out with a complete rewrite in Rust, fresh compatibility work for GNU ld and a change to how the linker handles corrupted input files. For developers, this is a substantial new version of a tool designed to link programmes quickly, with practical changes to its build setup and dependencies too.
Watch Desk analysis
What happened
Phoronix reports that Mold 3.0 replaces version 2.42.1 and focuses in particular on closing compatibility gaps with GNU ld, including support for linker scripts. The report also says the release improves safety when handling corrupted input files and resolves numerous bugs. Read Phoronix’s report.
The rewrite moves Mold from C++ to Rust. The new version requires Rust 1.95 or later, drops its Intel oneTBB dependency, and uses Cargo rather than CMake.
Why it matters
A linker sits in the build process turning compiled pieces into a working programme. Compatibility with GNU ld matters when projects rely on its behaviour or linker scripts; a drop-in replacement is only useful if it fits the build people already have. The reported compatibility work makes Mold 3.0 more interesting to teams considering it, though they will still want to test their own builds.
The language and build-system changes also have a practical cost: projects adopting this version need a sufficiently recent Rust toolchain and may need to adjust how they build Mold itself. Removing one dependency may simplify that setup, but the release is not quite a version-number-only upgrade.
Our read
This is a proper developer-tool release: a major rewrite paired with concrete work on compatibility and input handling. If Mold is already in your build chain, check the Rust requirement and try your project’s linker scripts before upgrading. Speed is the point of a fast linker; compatibility is what lets it stay invited.
What to watch
- Whether projects using GNU ld linker scripts work as expected with Mold 3.0.
- What the Rust 1.95 minimum means for teams with older build environments.
- How the compatibility and input-handling changes perform in real-world use.
Discussion spark: Would you switch a project to a rewritten Rust linker for better GNU ld compatibility, or wait until it has been tested against your own build scripts?
Sources and evidence
- Mold 3.0 High Speed Linker Released Following Rust Rewrite (5 October 2026, 10:29 UTC)
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