{"api_version":"1","generated_at":"2026-04-08T12:43:59+00:00","cve":"CVE-2023-34459","urls":{"html":"https://cve.report/CVE-2023-34459","api":"https://cve.report/api/cve/CVE-2023-34459.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2023-34459","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-34459"},"summary":{"title":"CVE-2023-34459","description":"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.","state":"PUBLIC","assigner":"security-advisories@github.com","published_at":"2023-06-16 23:15:00","updated_at":"2023-06-26 18:50:00"},"problem_types":["CWE-354"],"metrics":[],"references":[{"url":"https://github.com/OpenZeppelin/openzeppelin-contracts/commit/4d2383e17186be3e8ccf5a442e9686ecc7de1c55","name":"https://github.com/OpenZeppelin/openzeppelin-contracts/commit/4d2383e17186be3e8ccf5a442e9686ecc7de1c55","refsource":"MISC","tags":[],"title":"Merge pull request from GHSA-wprv-93r4-jj2p · OpenZeppelin/openzeppelin-contracts@4d2383e · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-wprv-93r4-jj2p","name":"https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-wprv-93r4-jj2p","refsource":"MISC","tags":[],"title":"MerkleProof multiproofs may allow proving arbitrary leaves for specific trees · Advisory · OpenZeppelin/openzeppelin-contracts · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.2","name":"https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.2","refsource":"MISC","tags":[],"title":"Release v4.9.2 · OpenZeppelin/openzeppelin-contracts · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2023-34459","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-34459","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2023","cve_id":"34459","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"openzeppelin","cpe5":"contracts","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"node.js","cpe12":"*","cpe13":"*"},{"cve_year":"2023","cve_id":"34459","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"openzeppelin","cpe5":"contracts_upgradeable","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"node.js","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"data_version":"4.0","data_type":"CVE","data_format":"MITRE","CVE_data_meta":{"ID":"CVE-2023-34459","ASSIGNER":"security-advisories@github.com","STATE":"PUBLIC"},"description":{"description_data":[{"lang":"eng","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."}]},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-354: Improper Validation of Integrity Check Value","cweId":"CWE-354"}]}]},"affects":{"vendor":{"vendor_data":[{"vendor_name":"OpenZeppelin","product":{"product_data":[{"product_name":"openzeppelin-contracts","version":{"version_data":[{"version_affected":"=","version_value":">= 4.7.0, < 4.9.2"}]}}]}}]}},"references":{"reference_data":[{"url":"https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-wprv-93r4-jj2p","refsource":"MISC","name":"https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-wprv-93r4-jj2p"},{"url":"https://github.com/OpenZeppelin/openzeppelin-contracts/commit/4d2383e17186be3e8ccf5a442e9686ecc7de1c55","refsource":"MISC","name":"https://github.com/OpenZeppelin/openzeppelin-contracts/commit/4d2383e17186be3e8ccf5a442e9686ecc7de1c55"},{"url":"https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.2","refsource":"MISC","name":"https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.2"}]},"source":{"advisory":"GHSA-wprv-93r4-jj2p","discovery":"UNKNOWN"},"impact":{"cvss":[{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}]}},"nvd":{"publishedDate":"2023-06-16 23:15:00","lastModifiedDate":"2023-06-26 18:50:00","problem_types":["CWE-354"],"metrics":{"baseMetricV3":{"cvssV3":{"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}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:openzeppelin:contracts_upgradeable:*:*:*:*:*:node.js:*:*","versionStartIncluding":"4.7.0","versionEndExcluding":"4.9.2","cpe_name":[]},{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:openzeppelin:contracts:*:*:*:*:*:node.js:*:*","versionStartIncluding":"4.7.0","versionEndExcluding":"4.9.2","cpe_name":[]}]}]}},"legacy_mitre":{"record":null,"notes":[]}}}