Rust 1.98.1 fixes incorrect trait-object dispatch tables

Rust 1.98.1 fixes a compiler bug that could put a null pointer into a trait object’s dispatch table where a function pointer belonged. Code built with the affected 1.98.0 compiler could then exhibit undefined behaviour, including crashes. This is a compiler correctness fix rather than a new language feature, and updating the toolchain matters for affected builds.

Rust Release Team · Sep 3, 2026

Why it matters

A useful catch-up item for projects whose CI or development environment still pins Rust 1.98.0.

More context

Review your toolchain pin, update to a fixed compiler and rebuild affected binaries before running regression tests. The official announcement dates to September 3; this is not a release from today.

Keep in mind

The problem occurs under particular compilation circumstances, not in every Rust program. The announcement does not establish whether your binaries are affected.

Original read