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
References4
- github.com/RustCrypto/utils/security/advisories/GHSA-3rjw-m598-… ExploitVendor Advisory
- github.com/RustCrypto/utils/security/advisories/GHSA-3rjw-m598-… ExploitVendor Advisory
- github.com/RustCrypto/utils/commit/dba6c355c9f241e3726d5ec2a68f… Patch
- github.com/RustCrypto/utils/releases/tag/cmov-v0.5.4 Product
Metrics
- CVSS 3.1
-
3.3
LOW
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - CVSS 4.0
-
2.0
LOW
Score source: CNA
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 5 · as of 14 November 2026
- CWE
- CWE-758
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.