Rust advisories / ark-r1cs-std
Vulnerability CriticalRUSTSEC-2021-0075 · ark-r1cs-std
RUSTSEC-2021-0075: Flaw in `FieldVar::mul_by_inverse` allows unsound R1CS constraint systems
Short answerA security vulnerability in the ark-r1cs-std crate: Flaw in `FieldVar::mul_by_inverse` allows unsound R1CS constraint systems. GitHub rates it Critical. Fixed in 0.3.1: update to a fixed version.
| Crate | ark-r1cs-std |
|---|---|
| Type | Vulnerability (crypto-failure) |
| Affected versions | Before 0.3.1. |
| Fixed in | 0.3.1 |
| Severity | Critical (GitHub rating) |
| Published | 2021-07-08 |
| Last changed | 2023-11-08 |
| Also known as | CVE-2021-38194, GHSA-qj3v-q2vj-4c8h |
| Affected functions | ark_r1cs_std::FieldVar::mul_by_inverse |
What to do
- See which version you have:
cargo tree -i ark-r1cs-std(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p ark-r1cs-std. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for exampleark-r1cs-std = "0.3.1") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
Versions 0.2.0 to 0.3.0 of ark-r1cs-std did not enforce any constraints in the FieldVar::mul_by_inverse method, allowing a malicious prover to produce an unsound proof that passes all verifier checks. This method was used primarily in scalar multiplication for short_weierstrass::ProjectiveVar.
This bug was fixed in commit 47ddbaa, and was released as part of version 0.3.1 on crates.io.
References
- Package: crates.io/crates/ark-r1cs-std
- Advisory: rustsec.org/advisories/RUSTSEC-2021-0075.html
- Web: github.com/arkworks-rs/r1cs-std/pull/70
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Up next
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