GovernorCompatibilityBravo incorrect ABI encoding may lead to unexpected behaviorGHSA-m6w8-fq7v-ph4m
GHSA-m6w8-fq7v-ph4m is a security vulnerability in @openzeppelin/contracts. A fix is available for @openzeppelin/contracts — see the affected versions and patch details below.
Real-World Exposure
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.
@openzeppelin/contractsnpm@openzeppelin/contracts-upgradeablenpmDescription
Impact
The GovernorCompatibilityBravo module may lead to the creation of governance proposals that execute function calls with incorrect arguments due to bad ABI encoding. This happens if the proposal is created using explicit function signatures, e.g. a proposal to invoke the function foo(uint256) is created as propose([target], [0], ["foo(uint256)"], ["0x00..01"]). If the function selector is provided as part of the encoded proposal data the issue is not present, e.g. the same proposal is created as propose([target], [0], ["0x2fbebd3800..01"]), where 2fbebd38 is the function selector.
We've assessed the instances of this contract found on chain, and did not find any occurrence of this bug in the past. Proposal creation through Tally or OpenZeppelin Defender is not affected. The core Governor contract on its own is not affected.
Patches
A fix is included in version v4.4.2 of @openzeppelin/contracts and @openzeppelin/contracts-upgradeable.
Workarounds
Do not create proposals using explicit function signatures. Instead, use the propose function without the signatures argument, and create the proposal using the fully ABI-encoded function call including the function selector in the calldatas argument as explained above.
References
https://github.com/OpenZeppelin/openzeppelin-contracts/issues/3099
Credits
This issue was identified and reported by @GeraldHost.
For more information
If you have any questions, comments, or need assistance regarding this advisory, email us at [email protected].
To submit security reports please use our bug bounty on Immunefi.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @openzeppelin/contracts | ≥ 4.3.0&&< 4.4.2 | 4.4.2npm install @openzeppelin/contracts@4.4.2 |
| 📦npm | @openzeppelin/contracts-upgradeable | ≥ 4.3.0&&< 4.4.2 | 4.4.2npm install @openzeppelin/contracts-upgradeable@4.4.2 |
Detection & mitigation playbook
Open-source dependencyDetect
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 4.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m6w8-fq7v-ph4m is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is GHSA-m6w8-fq7v-ph4m in your dependencies?
Find it across npm, including transitive dependencies.