GHSA-f854-hpxv-cw9r

Drainage of FeeCollector's Block Transaction Fees in cronos

### Impact In Cronos nodes running versions before v0.6.5, it is possible to take transaction fees from Cosmos SDK's FeeCollector for the current block by sending a custom crafted MsgEthereumTx. User funds and balances are safe. ### Patches This problem has been patched in Cronos v0.6.5 on the mempool level. The next network upgrade with consensus-breaking changes will patch it on the consensus level. ### Workarounds There are no tested workarounds. All validator node operators are recommended to upgrade to Cronos v0.6.5 at their earliest possible convenience. ### Credits Thank you to @zb3 for reporting this issue on [Cronos Immunefi Bug Bounty Program](https://immunefi.com/bounty/cronos/), to @cyril-crypto for reproducing the issue and to @yihuang and @thomas-nguy for patching the issue on the CheckTx (mempool) and the DeliverTx (consensus) levels. ### For more information If you have any questions or comments about this advisory: * Open a discussion in [crypto-org-chain/cronos](https://github.com/crypto-org-chain/cronos/discussions/new) * Email us at [chain@crypto.org](mailto:chain@crypto.org)