CVE-2026-23519

Critical

Published: 15/01/2026(UTC)Translated: 05/08/2026(UTC)NVD NIST

Summary

RustCrypto CMOV prior to 0.4.4 contains a vulnerability on thumbv6m-none-eabi (Cortex M0, M0+ and M1) where the compiler emits non-constant time assembly when using cmovnz (portable version). This vulnerability is fixed in 0.4.4.

Risk Assessment

The vulnerability may lead to data leakage through side-channel attacks, especially in cryptographic operations.

Recommendation

Update the RustCrypto CMOV library to version 0.4.4 or later.

Original NVD description (English source)

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 (portable version). This vulnerability is fixed in 0.4.4.