"summary":"A denial-of-service issue can be used to crash Geth nodes during block processing",
"description":"Full details to be disclosed at a later date",
"description":"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. \nThe crash was in the `uint256` library, where a buffer [underflowed](https://github.com/holiman/uint256/blob/4ce82e695c10ddad57215bdbeafb68b8c5df2c30/uint256.go#L442).\n\n\tif `d == 0`, `dLen` remains `0`\n\nand https://github.com/holiman/uint256/blob/4ce82e695c10ddad57215bdbeafb68b8c5df2c30/uint256.go#L451 will try to access index `[-1]`.\n\nThe `uint256` library was first merged in this [commit](https://github.com/ethereum/go-ethereum/commit/cf6674539c589f80031f3371a71c6a80addbe454), on 2020-06-08. \nExploiting this vulnerabilty would cause all vulnerable nodes to drop off the network. \n\nThe issue was brought to our attention through a [bug report](https://github.com/ethereum/go-ethereum/issues/21367), showing a `panic` occurring on sync from genesis on the Ropsten network.\n \nIt 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.\n",
"summary":"A DoS vulnerability can make a LES server crash.",
"description":"A DoS vulnerability can make a LES server crash via malicious GetProofsV2 request from a connected LES client.\n\nThe vulnerability was patched in #21896.\n\nThis vulnerability only concern users explicitly running geth as a light server",
"summary":"A consensus-vulnerability in Geth could cause a chain split, where vulnerable versions refuse to accept the canonical chain.",
"description":"A flaw was repoted at 2020-08-11 by John Youngseok Yang (Software Platform Lab), where a particular sequence of transactions could cause a consensus failure.\n\n- Tx 1:\n - `sender` invokes `caller`.\n - `caller` invokes `0xaa`. `0xaa` has 3 wei, does a self-destruct-to-self\n - `caller` does a `1 wei` -call to `0xaa`, who thereby has 1 wei (the code in `0xaa` still executed, since the tx is still ongoing, but doesn't redo the selfdestruct, it takes a different path if callvalue is non-zero)\n\n-Tx 2:\n - `sender` does a 5-wei call to 0xaa. No exec (since no code). \n\nIn geth, the result would be that `0xaa` had `6 wei`, whereas OE reported (correctly) `5` wei. Furthermore, in geth, if the second tx was not executed, the `0xaa` would be destructed, resulting in `0 wei`. Thus obviously wrong. \n\nIt was determined that the root cause was this [commit](https://github.com/ethereum/go-ethereum/commit/223b950944f494a5b4e0957fd9f92c48b09037ad) from [this PR](https://github.com/ethereum/go-ethereum/pull/19953). The semantics of `createObject` was subtly changd, into returning a non-nil object (with `deleted=true`) where it previously did not if the account had been destructed. This return value caused the new object to inherit the old `balance`.\n",
"summary":"The client is not ready for the 'London' technical upgrade, and will deviate from the canonical chain when the London upgrade occurs (at block '12965000' around August 4, 2021.",
"description":"At (or around) August 4, Ethereum will undergo a technical upgrade called 'London'. Clients not upgraded will fail to progress on the canonical chain.",
Martin Holst Swende
3 years ago
committed by
GitHub