CVE-2020-26241
Shallow copy bug in geth
Impact
### 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 [security@ethereum.org](mailto:security@ethereum.org)
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/ethereum/go-ethereum | >= 1.9.7, < 1.9.17 | 1.9.17 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Ethereum | Go Ethereum | before 1.9.17 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://blog.ethereum.org/2020/11/12/geth_security_release/
- https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf
- https://github.com/advisories/GHSA-69v6-xc2j-r2jf
- https://nvd.nist.gov/vuln/detail/CVE-2020-26241
- https://github.com/ethereum/go-ethereum/commit/295693759e5ded05fec0b2fb39359965b60da785
- https://blog.ethereum.org/2020/11/12/geth_security_release