CVE-2026-23519
RustCrypto cmov: thumbv6m-none-eabi compiler emits non-constant time assembly when using cmovnz
- State
- Published
- Severity
- 8.9 High
- Published
- Jan 15, 2026
- Updated
- Jan 15, 2026
- Reserved
- Jan 13, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.9 High | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N | GitHub_M |
Weaknesses
- CWE-208 Observable Timing Discrepancy
Affected Products
| Product | Versions |
|---|---|
utilsRustCrypto |
|
References
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