For full security process refer to yearn-security repo.
The scope of the Bug Bounty program spans smart contracts utilized in the Yearn ecosystem – the Solidity and/or Vyper smart contracts in the contracts folder of the master branch of the yearn-protocol repo, including historical deployments that still see active use on Ethereum Mainnet associated with YFI, and excluding any contracts used in a test-only capacity (including test-only deployments).
Note: Other contracts, outside of the ones mentioned above, might be considered on a case by case basis, please, reach out to the Yearn development team for clarification.