{"cve":"CVE-2023-34234","nvd":{"published":"2023-06-07T18:15:09.977","modified":"2026-06-17T06:03:11.140","status":"Modified","description":"OpenZeppelin Contracts is a library for smart contract development. By frontrunning the creation of a proposal, an attacker can become the proposer and gain the ability to cancel it. The attacker can do this repeatedly to try to prevent a proposal from being proposed at all. This impacts the `Governor` contract in v4.9.0 only, and the `GovernorCompatibilityBravo` contract since v4.3.0. This problem has been patched in 4.9.1 by introducing opt-in frontrunning protection. Users are advised to upgrade. Users unable to upgrade may submit the proposal creation transaction to an endpoint with frontrunning protection as a workaround.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-862"],"references":["https://github.com/OpenZeppelin/openzeppelin-contracts/commit/d9474327a492f9f310f31bc53f38dbea56ed9a57","https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-5h3x-9wvq-w4m2","https://github.com/OpenZeppelin/openzeppelin-contracts/commit/d9474327a492f9f310f31bc53f38dbea56ed9a57","https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-5h3x-9wvq-w4m2"],"products":["openzeppelin:contracts","openzeppelin:contracts_upgradeable"],"source":"nvd","synced_at":"2026-10-19T21:38:24.161619714+00:00"},"epss":{"cve":"CVE-2023-34234","score":0.00595,"percentile":0.48437,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-5h3x-9wvq-w4m2","url":"https://osv.dev/vulnerability/GHSA-5h3x-9wvq-w4m2","summary":"OpenZeppelin Contracts's governor proposal creation may be blocked by frontrunning","modified":"2026-09-10T03:50:02.116353126Z","packages":[{"ecosystem":"npm","name":"@openzeppelin/contracts","purl":"pkg:npm/%40openzeppelin/contracts","ranges":[">=4.3.0 <4.9.1"],"fixed":["4.9.1"]},{"ecosystem":"npm","name":"@openzeppelin/contracts-upgradeable","purl":"pkg:npm/%40openzeppelin/contracts-upgradeable","ranges":[">=4.3.0 <4.9.1"],"fixed":["4.9.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}