How severe is GHSA-5h3x-9wvq-w4m2?

GHSA-5h3x-9wvq-w4m2 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-5h3x-9wvq-w4m2?

GHSA-5h3x-9wvq-w4m2 affects the following packages: @openzeppelin/contracts (npm), @openzeppelin/contracts-upgradeable (npm). Ecosystems affected: npm.

How do I fix GHSA-5h3x-9wvq-w4m2?

Update @openzeppelin/contracts to 4.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5h3x-9wvq-w4m2 is resolved across your whole dependency graph.

How do I detect GHSA-5h3x-9wvq-w4m2 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @openzeppelin/contracts, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-5h3x-9wvq-w4m2 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is GHSA-5h3x-9wvq-w4m2 actively exploited in the wild?

No public exploit code has been indexed for GHSA-5h3x-9wvq-w4m2 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-5h3x-9wvq-w4m2?

GHSA-5h3x-9wvq-w4m2 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 49th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-5h3x-9wvq-w4m2?

GHSA-5h3x-9wvq-w4m2 is classified as CWE-862 (CWE-862). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-5h3x-9wvq-w4m2 published, and has it been updated?

GHSA-5h3x-9wvq-w4m2 was published on June 8, 2023 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

OpenZeppelin Contracts's governor proposal creation may be blocked by frontrunningGHSA-5h3x-9wvq-w4m2

MEDIUMFix: OpenZeppelin/openzeppelin-contracts-upgradeable@66f390f

GHSA-5h3x-9wvq-w4m2 is a medium-severity (CVSS 5.3) CWE-862 vulnerability in @openzeppelin/contracts. A fix is available for @openzeppelin/contracts — see the affected versions and patch details below.

Also known asCVE-2023-34234

Published

Jun 8, 2023

Updated

Sep 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-5h3x-9wvq-w4m2.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs49th percentile — riskier than 49% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

4Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@openzeppelin/contractsnpm

1.4Mdownloads / week

@openzeppelin/contracts-upgradeablenpm

434Kdownloads / week

Description

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

https://www.coinspect.com/openzeppelin-governor-dos/

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@openzeppelin/contracts`	≥ 4.3.0&&< 4.9.1	4.9.1`npm install @openzeppelin/contracts@4.9.1`
📦npm	`@openzeppelin/contracts-upgradeable`	≥ 4.3.0&&< 4.9.1	4.9.1`npm install @openzeppelin/contracts-upgradeable@4.9.1`

Affected Products

2 products · 2 configurations

Application

contractsopenzeppelin

≥ 4.3.0 && < 4.9.1

range

Application

contracts upgradeableopenzeppelin

≥ 4.3.0 && < 4.9.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @openzeppelin/contracts, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @openzeppelin/contracts to 4.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5h3x-9wvq-w4m2 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### 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 Co