Vulnerability in Rustcrypto Cmov
CVE-2026-50185
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.
EPSS: 0.002 (5.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.
Affected products
- Rustcrypto Cmov
- Rustcrypto Utils — versions >= 0.1.1, < 0.5.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-50185?
- CVE-2026-50185 is a low-severity vulnerability in Rustcrypto Cmov, classified under CWE-758. CVSS score: 3.3/10. Published 2026-07-17.
- How severe is CVE-2026-50185?
- Low severity. CVSS v3 base score is 3.3 out of 10.