OpenZeppelin Contracts's governor proposal creation may be blocked by frontrunning
Impact
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.
Patches
The problem has been patched in 4.9.1 by introducing opt-in frontrunning protection.
Workarounds
Submit the proposal creation transaction to an endpoint with frontrunning protection.
Credit
Reported by Lior Abadi and Joaquin Pereyra from Coinspect.
References
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @openzeppelin/contracts | >= 4.3.0, < 4.9.1 | 4.9.1 |
| npm package | @openzeppelin/contracts-upgradeable | >= 4.3.0, < 4.9.1 | 4.9.1 |
References
- https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-5h3x-9wvq-w4m2
- https://nvd.nist.gov/vuln/detail/CVE-2023-34234
- https://github.com/OpenZeppelin/openzeppelin-contracts-upgradeable/commit/66f390fa516b550838e2c2f65132b5bc2afe1ced
- https://github.com/OpenZeppelin/openzeppelin-contracts/commit/d9474327a492f9f310f31bc53f38dbea56ed9a57
- https://github.com/OpenZeppelin/openzeppelin-contracts
- https://github.com/OpenZeppelin/openzeppelin-contracts/releases/tag/v4.9.1
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- Weakness (CWE)
CWE-862- Platform
- npm
- Package
@openzeppelin/contracts, @openzeppelin/contracts-upgradeable- Disclosed
- 08.06.2023
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-5h3x-9wvq-w4m2 - CC BY 4.0
Vulnerability history: @openzeppelin/contracts
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 20
- First → latest
- 08.2021 07.2025
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
- High 5
- Medium 12
- Low 1
Disclosures per year
- 2021: 4
- 2022: 7
- 2023: 7
- 2024: 1
- 2025: 1
- 2026: 0
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OpenZeppelin Contracts's governor proposal creation may be blocked by frontrunning this entry
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