{
  "id": "CVE-2023-34459",
  "sourceIdentifier": "security-advisories@github.com",
  "published": "2023-06-16T23:15:08.817",
  "lastModified": "2023-06-26T18:50:28.553",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "OpenZeppelin Contracts is a library for smart contract development. Starting in version 4.7.0 and prior to version 4.9.2, when the `verifyMultiProof`, `verifyMultiProofCalldata`, `procesprocessMultiProof`, or `processMultiProofCalldat` functions are in use, it is possible to construct merkle trees that allow forging a valid multiproof for an arbitrary set of leaves.\n\nA 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 inadvertedly 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.\n\nA 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.\n\nThe problem has been patched in version 4.9.2.\n\nSome workarounds are available. For those 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."
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "nvd@nist.gov",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6
      },
      {
        "source": "security-advisories@github.com",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 3.6
      }
    ]
  },
  "weaknesses": [
    {
      "source": "security-advisories@github.com",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-354"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:openzeppelin:contracts:*:*:*:*:*:node.js:*:*",
              "versionStartIncluding": "4.7.0",
              "versionEndExcluding": "4.9.2",
              "matchCriteriaId": "60DC44CD-28DE-44B0-A762-9D2C8A9D5B8B"
            },
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:openzeppelin:contracts_upgradeable:*:*:*:*:*:node.js:*:*",
              "versionStartIncluding": "4.7.0",
              "versionEndExcluding": "4.9.2",
              "matchCriteriaId": "8AEC1B37-B265-430B-B6B6-434A5CFC6B04"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/OpenZeppelin/openzeppelin-contracts/commit/4d2383e17186be3e8ccf5a442e9686ecc7de1c55",
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.2",
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-wprv-93r4-jj2p",
      "source": "security-advisories@github.com",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}