{
"id": "GHSA-jm5c-rv3w-w83m",
"aliases": [
"CVE-2020-26242"
],
"details": "### Impact\nDenial-of-service (crash) during block processing\n\n### Details\n\nAffected 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\n- https://github.com/holiman/uint256/releases/tag/v1.1.1 was made the same day, \n- PR to address the issue: https://github.com/holiman/uint256/pull/80 \n- PR to update geth deps: https://github.com/ethereum/go-ethereum/pull/21368 \n\n\n\n### Patches\n\nUpgrade to v1.9.18 or higher\n\n### Workarounds\n\nNot at this time\n\n### References\n\nhttps://blog.ethereum.org/2020/11/12/geth_security_release/\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [go-ethereum](https://github.com/ethereum/go-ethereum)\n* Email us at [[email protected] ](mailto:[email protected] )\n",
"summary": "Denial of service in geth",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "1.9.16"
},
{
"fixed": "1.9.18"
}
]
}
],
"package": {
"name": "github.com/ethereum/go-ethereum",
"ecosystem": "Go"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0.1.0"
},
{
"fixed": "1.1.1"
}
]
}
],
"package": {
"name": "github.com/holiman/uint256",
"ecosystem": "Go"
}
}
],
"modified": "2025-01-30T14:38:53Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
}
],
"published": "2021-06-29T21:13:20Z",
"references": [
{
"url": "https://github.com/ethereum/go-ethereum/security/advisories/GHSA-jm5c-rv3w-w83m",
"type": "WEB"
},
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-26242",
"type": "ADVISORY"
},
{
"url": "https://github.com/holiman/uint256/pull/80",
"type": "WEB"
},
{
"url": "https://github.com/ethereum/go-ethereum/commit/7163a6664ee664df81b9028ab3ba13b9d65a7196",
"type": "WEB"
},
{
"url": "https://github.com/holiman/uint256/commit/6785da6e3eea403260a5760029e722aa4ff1716d",
"type": "WEB"
},
{
"url": "https://blog.ethereum.org/2020/11/12/geth_security_release",
"type": "WEB"
},
{
"url": "https://github.com/ethereum/go-ethereum",
"type": "PACKAGE"
},
{
"url": "https://pkg.go.dev/vuln/GO-2021-0103",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-125",
"CWE-191",
"CWE-400"
],
"severity": "MODERATE",
"github_reviewed": true,
"nvd_published_at": null,
"github_reviewed_at": "2021-05-21T21:50:44Z"
}
}