CVE-2023-34459

MEDIUM5.3EPSS 0.86%

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

發布日:2023/6/19修改日:2023/11/8

描述

### 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.

受影響套件(2)

CVSS 分數

來源版本嚴重程度向量
osvCVSS 3.1MEDIUM5.3CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

參考連結(5)