GHSA-69v6-xc2j-r2jf

Shallow copy bug in geth

Source: GitHub Advisory Database (reviewed) Moderate CVE-2020-26241

Packages

Ecosystem	Package	Affected	Fixed in
Go	github.com/ethereum/go-ethereum	>= 1.9.7, < 1.9.17	1.9.17

Details

As written in the advisory (Markdown source, shown as plain text).

### 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])

References

External links from the advisory. They lead to third-party sites.