GovernorCompatibilityBravo incorrect ABI encoding may lead to unexpected behavior
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 security@openzeppelin.com.
To submit security reports please use our bug bounty on Immunefi.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @openzeppelin/contracts | >= 4.3.0, < 4.4.2 | 4.4.2 |
| npm package | @openzeppelin/contracts-upgradeable | >= 4.3.0, < 4.4.2 | 4.4.2 |
References
- Weakness (CWE)
-- Platform
- npm
- Package
@openzeppelin/contracts, @openzeppelin/contracts-upgradeable- Disclosed
- 13.01.2022
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-m6w8-fq7v-ph4m - 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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GovernorCompatibilityBravo incorrect ABI encoding may lead to unexpected behavior this entry
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