| Package | Affected versions | Patched versions |
|---|---|---|
| github.com/ethereum/go-ethereum | ≥ 1.9.16, < 1.9.18 | 1.9.18 |
| github.com/holiman/uint256 | ≥ 0.1.0, < 1.1.1 | 1.1.1 |
| go ethereum | < 1.9.18 | 1.9.18 |
Denial-of-service (crash) during block processing
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.
Upgrade to v1.9.18 or higher
Not at this time
https://blog.ethereum.org/2020/11/12/geth_security_release/
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