RUSTSEC-2023-0055: Multiple soundness issues

What to do

1. See which version you have: cargo tree -i lexical (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p lexical. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example lexical = "7.0.0") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

lexical contains multiple soundness issues:

1. Bytes::read() allows creating instances of types with invalid bit patterns 1. BytesIter::read() advances iterators out of bounds 1. The BytesIter trait has safety invariants but is public and not marked unsafe 1. write_float() calls MaybeUninit::assume_init() on uninitialized data, which is is not allowed by the Rust abstract machine 1. radix() calls MaybeUninit::assume_init() on uninitialized data, which is is not allowed by the Rust abstract machine

The crate also has some correctness issues.

Alternatives

For quickly parsing floating-point numbers third-party crates are no longer needed. A fast float parsing algorithm by the author of lexical has been merged into libcore.

For quickly parsing integers, consider atoi and btoi crates (100% safe code). atoi_radix10 provides even faster parsing, but only with -C target-cpu=native, and at the cost of some unsafe.

For formatting integers in a #[no_std] context consider the numtoa crate.

For working with big numbers consider num-bigint and num-traits.

References

• Package: crates.io/crates/lexical
• Advisory: rustsec.org/advisories/RUSTSEC-2023-0055.html
• Report: github.com/Alexhuszagh/rust-lexical/issues/102
• Report: github.com/Alexhuszagh/rust-lexical/issues/101
• Report: github.com/Alexhuszagh/rust-lexical/issues/95
• Report: github.com/Alexhuszagh/rust-lexical/issues/104
• Report: github.com/Alexhuszagh/rust-lexical/issues/126

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.