RUSTSEC-2026-0387None▾ SunlitMultiple timing variability issues in operations intended to be constant-time
▾ Sunlit zone — Low / medium · no exploitation signal
impact 2.8 · likelihood 0 · exploitation 0
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Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
Several operations intended to be constant-time could execute secret-dependent branches, depending on the compiler and target CPU. These include subtraction, zero counting, division, and Montgomery multiplication.
Additionally, UintRef equality could terminate at the first unequal limb,
and BoxedMontyForm::invert branched on whether an inverse exists.
Applications using affected operations on secret integers may leak information through timing or microarchitectural side channels. This includes information about intermediate arithmetic values, matching limbs, and invertibility.
Such leakage could potentially enable recovery of cryptographic secrets. Practical exploitability depends on the downstream algorithm, compiler, target CPU, and an attacker's ability to observe the side channel.
Upgrade to v0.7.6, which removes the identified branches, updates ctutils to
include its constant-time fixes, and adds BINSEC-based regression checks using
cargo checkct for arithmetic on multiple targets.
crypto-bigint >= 0.0.0-0, < 0.7.6Upgrade to a patched release:
crypto-bigint 0.7.6