GHSA-jm5c-rv3w-w83m Denial of service in geth

• Go github.com/ethereum/go-ethereum: >= 1.9.16, < 1.9.18 → fixed in 1.9.18 • Go github.com/holiman/uint256: >= 0.1.0, < 1.1.1 → fixed in 1.1.1

Impact Denial-of-service (crash) during block processing Details Affected versions suffer from a vulnerability which can be exploited through the `MULMOD` operation, by specifying a modulo of `0`: `mulmod(a,b,0)`, causing a `panic` in the underlying library. The crash was in the `uint256` library, where a buffer underflowed. if `d == 0`, `dLen` remains `0` and https://github.com/holiman/uint256/blob/4ce82e695c10ddad57215bdbeafb68b8c5df2c30/uint256.go#L451 will try to access index `[-1]`. The `uint256` library was first merged in this commit, on 2020-06-08. Exploiting this vulnerabilty would cause all vulnerable nodes to drop off the network. The issue was brought to our attention through a bug report, showing a `panic` occurring on sync from genesis on the Ropsten network. It was estimated that the least obvious way to fix this would be to merge the fix into `uint256`, make a new release of that library and then update the geth-dependency. • https://github.com/holiman/uint256/releases/tag/v1.1.1 was made the same day, • PR to address the issue: https://github.com/holiman/uint256/pull/80 • PR to update geth deps: https://github.com/ethereum/go-ethereum/pull/21368 Patches Upgrade to v1.9.18 or higher Workarounds Not at this time 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 • Email us at [email protected]