CVE-2021-43839

Cronos is a commercial implementation of a blockchain. 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. This problem has been patched in Cronos v0.6.5. There are no tested workarounds. All validator node operators are recommended to upgrade to Cronos v0.6.5 at their earliest possible convenience.

Cronos is a commercial implementation of a blockchain. 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. This problem has been patched in Cronos v0.6.5. There are no tested workarounds. All validator node operators are recommended to upgrade to Cronos v0.6.5 at their earliest possible convenience.

### 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)

### 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)

Cronos es una implementación comercial de una cadena de bloques. En los nodos de Cronos que ejecutan versiones anteriores a la v0.6.5, es posible tomar las tasas de transacción del FeeCollector de Cosmos SDK para el bloque actual mediante el envío de un MsgEthereumTx diseñado a medida. Este problema ha sido parcheado en Cronos versión v0.6.5. No se presentan soluciones probadas. Se recomienda a todos los operadores de nodos comprobadores que actualicen a Cronos versión v0.6.5 lo antes posible