GHSA-wprv-93r4-jj2p

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    GHSA-wprv-93r4-jj2p

    Published: 19 Jun 2023Last Modified: 10 Sept 2026

    Summary: OpenZeppelin Contracts using MerkleProof multiproofs may allow proving arbitrary leaves for specific trees

    Details: ### 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](https://github.com/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](https://www.npmjs.com/package/@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.

    References: https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-wprv-93r4-jj2p, https://nvd.nist.gov/vuln/detail/CVE-2023-34459, https://github.com/OpenZeppelin/openzeppelin-contracts/commit/4d2383e17186be3e8ccf5a442e9686ecc7de1c55, https://github.com/OpenZeppelin/openzeppelin-contracts, https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.2

    Affected packages

    Package

    Name: @openzeppelin/contracts

    Purl: pkg:npm/%40openzeppelin/contracts

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 4.7.0
    Fixed -4.9.2

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    GHSA-wprv-93r4-jj2p | CVE-DB