CVE-2021-43839
Drainage of FeeCollector's Block Transaction Fees in cronos
Description
### 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 [[email protected]](mailto:[email protected])
How to fix CVE-2021-43839
To remediate CVE-2021-43839, upgrade the affected package to a fixed version below.
- —upgrade to 0.6.5 or later
- —upgrade to 0.10.0 or later
- —no fix listed
Is CVE-2021-43839 being exploited?
Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 0.6.5
- >= 0.8.0, < 0.10.0
- from 0, <= 0.4.2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |