GHSA-wprv-93r4-jj2p
MEDIUMOpenZeppelin Contracts using MerkleProof multiproofs may allow proving arbitrary leaves for specific trees
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@openzeppelin/contractsnpm@openzeppelin/contracts-upgradeablenpmDescription
Impact
When the verifyMultiProof, verifyMultiProofCalldata, processMultiProof, or processMultiProofCalldata functions are in use, it is possible to construct merkle trees that allow forging a valid multiproof for an arbitrary set of leaves.
A contract may be vulnerable if it uses multiproofs for verification and the merkle tree that is processed includes a node with value 0 at depth 1 (just under the root). This could happen inadvertently for balanced trees with 3 leaves or less, if the leaves are not hashed. This could happen deliberately if a malicious tree builder includes such a node in the tree.
A contract is not vulnerable if it uses single-leaf proving (verify, verifyCalldata, processProof, or processProofCalldata), or if it uses multiproofs with a known tree that has hashed leaves. Standard merkle trees produced or validated with the @openzeppelin/merkle-tree library are safe.
Patches
The problem has been patched in 4.9.2.
Workarounds
If you are using multiproofs: When constructing merkle trees hash the leaves and do not insert empty nodes in your trees. Using the @openzeppelin/merkle-tree package eliminates this issue. Do not accept user-provided merkle roots without reconstructing at least the first level of the tree. Verify the merkle tree structure by reconstructing it from the leaves.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @openzeppelin/contracts | ≥ 4.7.0&&< 4.9.2 | 4.9.2 |
| 📦npm | @openzeppelin/contracts-upgradeable | ≥ 4.7.0&&< 4.9.2 | 4.9.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @openzeppelin/contracts. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @openzeppelin/contracts to 4.9.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wprv-93r4-jj2p 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 pinpoints whether GHSA-wprv-93r4-jj2p is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-wprv-93r4-jj2p. 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-wprv-93r4-jj2p in your dependencies?
O3 detects GHSA-wprv-93r4-jj2p across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.