CVE-2023-30542: GovernorCompatibilityBravo may trim proposal calldata

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-04-16 · updated 2026-06-17
Weakness: CWE-20

Description

OpenZeppelin Contracts is a library for secure smart contract development. The proposal creation entrypoint (`propose`) in `GovernorCompatibilityBravo` allows the creation of proposals with a `signatures` array shorter than the `calldatas` array. This causes the additional elements of the latter to be ignored, and if the proposal succeeds the corresponding actions would eventually execute without any calldata. The `ProposalCreated` event correctly represents what will eventually execute, but the proposal parameters as queried through `getActions` appear to respect the original intended calldata. This issue has been patched in 4.8.3. As a workaround, ensure that all proposals that pass through governance have equal length `signatures` and `calldatas` parameters.

Affected products

openzeppelin-contracts: from 4.3.0 before 4.8.3 — fixed in 4.8.3
OpenZeppelin Contracts Upgradeable: from 4.3.0 before 4.8.3 — fixed in 4.8.3

How to fix

Upgrade to a fixed version: openzeppelin-contracts 4.8.3; OpenZeppelin Contracts Upgradeable 4.8.3. Check the vendor advisory for mitigations.

References

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