ASA-2024-006: ValidateVoteExtensions helper function in Cosmos SDK may allow incorrect voting power assumptions

Summary

## ASA-2024-006: ValidateVoteExtensions helper function may allow incorrect voting power assumptions **Component**: Cosmos SDK **Criticality**: High **Affected Versions**: Cosmos SDK versions <= 0.50.4, on 0.50 branches **Affected Users**: Chain developers, Validator and Node operators **Impact**: Elevation of Privilege ## Summary The default `ValidateVoteExtensions` helper function infers total voting power based off of the injected `VoteExtension`, which are injected by the proposer. If your chain utilizes the `ValidateVoteExtensions` helper in `ProcessProposal`, a dishonest proposer can potentially mutate voting power of each validator it includes in the injected `VoteExtension`, which could have potentially unexpected or negative consequences on modified state. Additional validation on injected `VoteExtension` data was added to confirm voting power against the state machine. ## Next Steps for Impacted Parties If you are a chain developer on an affected version of the Cosmos SDK, it is advised to update to the latest available version of the Cosmos SDK for your project. Once a patched version is available, it is recommended that network operators upgrade. A Github Security Advisory for this issue is available in the Cosmos-SDK [repository](https://github.com/cosmos/cosmos-sdk/security/advisories/GHSA-95rx-m9m5-m94v). For more information about Cosmos SDK, see https://docs.cosmos.network/.