{"id":"CVE-2021-42766","aliases":["EUVD-2021-29724","GHSA-xh87-56v2-2mrp"],"status":"published","title":"The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to...","description":"The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to cause a denial of service (long-range consensus chain reorganizations), even when this adversary has little stake and cannot influence network message propagation. This can cause a protocol stall, or an increase in the profits of individual validators.","severity":{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-11","score":0.00961,"percentile":0.62009,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"published":"2021-10-20T19:27:43Z","modified":"2026-06-17T04:10:06Z","products":[{"vendor":"proof-of-stake_ethereum_project","product":"proof-of-stake_ethereum"}],"references":[{"url":"https://arxiv.org/abs/2110.10086","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-42766"},{"url":"https://github.com/advisories/GHSA-xh87-56v2-2mrp"}],"sources":{"cve":[{"id":"CVE-2021-42766","description":"The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to cause a denial of service (long-range consensus chain reorganizations), even when this adversary has little stake and cannot influence network message propagation. This can cause a protocol stall, or an increase in the profits of individual validators.","status":"published","published":"2021-10-20T19:27:43Z","modified":"2024-08-04T03:38:50.211Z","updated_at":"2026-11-02T14:32:58.739039Z"}],"euvd":[{"id":"EUVD-2021-29724","description":"The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to cause a denial of service (long-range consensus chain reorganizations), even when this adversary has little stake and cannot influence network message propagation. This can cause a protocol stall, or an increase in the profits of individual validators.","status":"published","published":"2021-10-20T19:27:43Z","modified":"2024-08-04T03:38:50Z","updated_at":"2026-11-03T03:24:15.299027Z"}],"ghsa":[{"id":"GHSA-xh87-56v2-2mrp","title":"The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to...","description":"The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to cause a denial of service (long-range consensus chain reorganizations), even when this adversary has little stake and cannot influence network message propagation. This can cause a protocol stall, or an increase in the profits of individual validators.","status":"published","published":"2022-05-24T19:18:03Z","modified":"2023-01-30T05:03:07Z","updated_at":"2026-11-02T14:46:46.047512Z"}],"nvd":[{"id":"CVE-2021-42766","description":"The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to cause a denial of service (long-range consensus chain reorganizations), even when this adversary has little stake and cannot influence network message propagation. This can cause a protocol stall, or an increase in the profits of individual validators.","status":"published","published":"2021-10-20T20:15:07.517Z","modified":"2026-06-17T04:10:06.53Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":6.4,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:P","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:07:00.137719Z"}]}}