GHSA-69v6-xc2j-r2jf

### Impact
This is a Consensus vulnerability, which can be used to cause a chain-split where vulnerable nodes reject the canonical chain.

Geth’s pre-compiled `dataCopy` (at `0x00...04`) contract did a shallow copy on invocation. An attacker could deploy a contract that

- writes `X` to an EVM memory region `R`,
- calls `0x00..04` with `R` as an argument,
- overwrites `R` to `Y`,
- and finally invokes the `RETURNDATACOPY` opcode.

When this contract is invoked, a consensus-compliant node would push `X` on the EVM stack, whereas Geth would push `Y`.

### Patches

No standalone patches have been made.

### Workarounds

Upgrade to `1.9.17` or higher.

### References

https://blog.ethereum.org/2020/11/12/geth_security_release/

### For more information
If you have any questions or comments about this advisory:
* Open an issue in [go-ethereum](https://github.com/ethereum/go-ethereum)
* Email us at [[email protected]](mailto:[email protected])