GHSA-7p92-x423-vwj6 — gnark
Fix: Consensys/gnark@3421eaaGHSA-7p92-x423-vwj6 is a security vulnerability in github.com/consensys/gnark. A fix is available for github.com/consensys/gnark — see the affected versions and patch details below.
Plonk verifier KZG multi point verification
Real-World Exposure
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Description
Impact
The vulnerability allows a third party to derive a valid proof from a valid initial tuple {proof, public_inputs}, corresponding to the same public inputs as the initial proof. It is due to a randomness being generated using a small part of the scratch memory describing the state, allowing for degrees of freedom in the transcript.
Note that the impact is limited to the PlonK verifier smart contract.
Patches
We still use a hash function on some data to have a pseudo rng, but instead of hashing the first 32 bytes of the state (
let random := mod(keccak256(state, 0x20), r_mod) )
we hash the whole state at this point of the verifier as if it was a Fiat Shamir transcript:
mstore(mPtr, mload(add(state, STATE_FOLDED_DIGESTS_X)))
mstore(add(mPtr, 0x20), mload(add(state, STATE_FOLDED_DIGESTS_Y)))
mstore(add(mPtr, 0x40), calldataload(add(aproof, PROOF_BATCH_OPENING_AT_ZETA_X)))
mstore(add(mPtr, 0x60), calldataload(add(aproof, PROOF_BATCH_OPENING_AT_ZETA_Y)))
mstore(add(mPtr, 0x80), calldataload(add(aproof, PROOF_GRAND_PRODUCT_COMMITMENT_X)))
mstore(add(mPtr, 0xa0), calldataload(add(aproof, PROOF_GRAND_PRODUCT_COMMITMENT_Y)))
mstore(add(mPtr, 0xc0), calldataload(add(aproof, PROOF_OPENING_AT_ZETA_OMEGA_X)))
mstore(add(mPtr, 0xe0), calldataload(add(aproof, PROOF_OPENING_AT_ZETA_OMEGA_Y)))
mstore(add(mPtr, 0x100), mload(add(state, STATE_ZETA)))
mstore(add(mPtr, 0x120), mload(add(state, STATE_GAMMA_KZG)))
let random := staticcall(gas(), 0x2, mPtr, 0x140, mPtr, 0x20)
Workarounds
In the function batch_verify_multi_points, the variable random (corresponding to u in the paper, step 12 of the plonk verification process) should depend on state_folded_digests_x, state_folded_digests_y, proof_grand_product_commitment_x, proof_grand_product_commitment_y and state_zeta (by hashing those values for instance).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/consensys/gnark | all versions | 0.9.1go get github.com/consensys/gnark@v0.9.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/consensys/gnark, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/consensys/gnark to 0.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7p92-x423-vwj6 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-7p92-x423-vwj6 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-7p92-x423-vwj6. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-7p92-x423-vwj6 in your dependencies?
O3 Security finds GHSA-7p92-x423-vwj6 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.