CVE-2026-23519
Critical
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. 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.
SeverityCritical
CVSS9.8
Exploit probability—
ProductRustcrypto Cmov
PublishedJan 15, 2026
First seenJan 15, 2026
Weakness typeCWE-208CWE-208
How to fix
Update
- rustcrypto cmov0.4.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| rustcrypto cmov | v < 0.4.4 | 0.4.4 |
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