GHSA-m6w8-fq7v-ph4m
GovernorCompatibilityBravo incorrect ABI encoding may lead to unexpected behavior
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@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 | 4.4.2 |
| 📦npm | @openzeppelin/contracts-upgradeable | ≥ 4.3.0&&< 4.4.2 | 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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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.
How O3 protects you
O3 pinpoints whether GHSA-m6w8-fq7v-ph4m is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-m6w8-fq7v-ph4m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-m6w8-fq7v-ph4m in your dependencies?
O3 detects GHSA-m6w8-fq7v-ph4m across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.