CVE-2026-50185: Rustcrypto Cmov

Low severity, CVSS 3.3. EPSS: 0.2% chance of exploitation in the next 30 days.

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. From 0.1.1 until 0.5.4, the aarch64 implementations of Cmov and CmovEq in cmov/src/backends/aarch64.rs assume high bits are zero-extended when loading values smaller than a register, so set high bits such as [8..] in a Cmov selector or [16..] of self or other in the u16 and i16 CmovEq implementations can cause left.cmovz(&right, condition) to produce incorrect output. This issue is fixed in version 0.5.4.

Affected products

• Rustcrypto Cmov: from 0.1.1, before 0.5.4 (fixed in 0.5.4)

Published 2026-07-17. Last modified 2026-08-18.