What’s Vulnerable › Vulnerabilities

CVE-2026-50185: RustCrypto Cmov/CmovEq on aarch64 can produce wrong results if high-bits of registers are set

• Severity: low (CVSS 3.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-17 · updated 2026-10-24
• Weakness: CWE-758

Description

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

How to fix

Upgrade to a fixed version: RustCrypto Cmov 0.5.4. Check the vendor advisory for mitigations.

References

• https://github.com/RustCrypto/utils/commit/dba6c355c9f241e3726d5ec2a68f9f3b519f6063
• https://github.com/RustCrypto/utils/releases/tag/cmov-v0.5.4
• https://github.com/RustCrypto/utils/security/advisories/GHSA-3rjw-m598-pq24
• https://github.com/RustCrypto/utils/security/advisories/GHSA-3rjw-m598-pq24

Get alerted when CVE-2026-50185 or the next vulnerability affects your stack