Reported

October 14, 2023

Issued

November 10, 2024

Package

simd-json-derive (crates.io)

Type

INFO Unsound

Keywords

#panic #undefined-behavior

References

• https://github.com/simd-lite/simd-json-derive/issues/67

Patched

• >=0.12.0

Description

An invalid use of MaybeUninit::uninit().assume_init() in simd-json-derive's derive macro can cause undefined behavior. The original code used MaybeUninit to avoid initialisation of the struct and then set the fields using ptr::write. The undefined behavior triggered by this misuse of MaybeUninit can lead to invlaid memory access and panics in binaries compiled in release mode (aka simd-json-derive prior to version 0.12 has UB and optimizes into some nonsense)

The 0.12.0 removes this section of code, avoiding the use of MaybeUninit alltogether.

Advisory available under CC0-1.0 license.