Rust 1.98.1 landed on September 3 to correct a compiler bug in 1.98.0 that generated broken trait-object vtables and could crash programs.
A Rust issue opened August 21 found rustc could emit a null pointer where a function pointer belonged, producing undefined behavior—sometimes a segfault, potentially arbitrary effects.
The fix follows quickly after the Rust 1.98.0 release, which had introduced algebraic methods for floating-point addition, subtraction, multiplication, division and remainder.
Users on earlier stable versions can install the update with rustup update stable, while the Rust team urged developers to test beta and nightly builds and report bugs.