CVE-2026-23519: Observable Timing Discrepancy

RustCrypto CMOV provides conditional move CPU intrinsics which are guaranteed on major platforms to execute in constant-time and not be rewritten as branches by the compiler. Prior to 0.4.4, the thumbv6m-none-eabi Cortex M0, M0+ and M1 compiler emits non-constant time assembly when using cmovnz...

Non-constant-time code generation on ARM32 targets

Summary While the cmov crate has a special backend for aarch64 which uses special CSEL instructions, on 32-bit ARM it uses a portable pure Rust fallback implementation. This implementation uses a combination of bitwise arithmetic and core::hint::blackbox to attempt to coerce constant-time code...

RUSTSEC-2026-0003 Non-constant-time code generation on ARM32 targets

Summary While the cmov crate has a special backend for aarch64 which uses special CSEL instructions, on 32-bit ARM it uses a portable pure Rust fallback implementation. This implementation uses a combination of bitwise arithmetic and core::hint::blackbox to attempt to coerce constant-time code...