{"id":"CVE-2020-26264","aliases":["GHSA-r33q-22hv-j29q","GO-2021-0063"],"url":"https://o3.security/vulnerability/CVE-2020-26264","summary":"Denial of service in github.com/ethereum/go-ethereum","details":"### Impact\n\nA DoS vulnerability can make a LES server crash via malicious `GetProofsV2` request from a connected LES client.\n\n### Patches\n\nThe vulnerability was patched in https://github.com/ethereum/go-ethereum/pull/21896. \n\n### Workarounds\n\nThis vulnerability only concerns users explicitly enabling `les` server; disabling `les` prevents the exploit. \nIt can also be patched by manually applying the patch in https://github.com/ethereum/go-ethereum/pull/21896. \n\n\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 [security@ethereum.org](mailto:security@ethereum.org)","published":"2020-12-11T17:15:12.793Z","modified":"2026-08-07T15:12:12.626129Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Go","name":"github.com/ethereum/go-ethereum","fixedVersion":"1.9.25"}],"fix":{"url":"https://github.com/ethereum/go-ethereum/commit/bddd103a9f0af27ef533f04e06ea429cf76b6d46","label":"ethereum/go-ethereum@bddd103"},"references":[{"type":"ADVISORY","url":"https://github.com/ethereum/go-ethereum/releases/tag/v1.9.25"},{"type":"ADVISORY","url":"https://github.com/ethereum/go-ethereum/security/advisories/GHSA-r33q-22hv-j29q"},{"type":"FIX","url":"https://github.com/ethereum/go-ethereum/commit/bddd103a9f0af27ef533f04e06ea429cf76b6d46"},{"type":"FIX","url":"https://github.com/ethereum/go-ethereum/pull/21896"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-26264"},{"type":"PACKAGE","url":"https://github.com/ethereum/go-ethereum"},{"type":"WEB","url":"https://pkg.go.dev/vuln/GO-2021-0063"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T15:12:12.626129Z"}}