{"id":"CVE-2021-20330","aliases":["BIT-mongodb-2021-20330","EUVD-2021-7750","GHSA-8jvf-jqg4-r6h2","UBUNTU-CVE-2021-20330"],"status":"published","title":"Specific replication command with malformed oplog entries can crash secondaries","description":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.27; MongoDB Server v4.2 versions prior to 4.2.16; MongoDB Server v4.4 versions prior to 4.4.9.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.0108,"percentile":0.6554,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-20"],"published":"2021-12-15T12:30:10Z","modified":"2026-10-24T14:51:05Z","fixes":[{"ecosystem":"Bitnami","package":"mongodb","fixed_in":["4.0.25","4.2.14","4.4.6"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Bitnami","package":"mongodb","ranges":[{"type":"SEMVER","events":[{"introduced":"4.0.0"},{"fixed":"4.0.25"},{"introduced":"4.2.0"},{"fixed":"4.2.14"},{"introduced":"4.4.0"},{"fixed":"4.4.6"}]}]}],"products":[{"vendor":"mongodb","product":"mongodb"},{"vendor":"mongodb inc.","product":"mongodb server"},{"vendor":"mongodb, inc.","product":"mongodb server"}],"references":[{"url":"https://jira.mongodb.org/browse/SERVER-36263","tags":["x_refsource_MISC","x_transferred","Issue Tracking","Patch","Vendor Advisory","advisory","fix","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20330","tags":["web"]},{"url":"https://github.com/advisories/GHSA-8jvf-jqg4-r6h2"},{"url":"https://ubuntu.com/security/CVE-2021-20330","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-20330","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-20330","title":"Specific replication command with malformed oplog entries can crash secondaries","description":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.27; MongoDB Server v4.2 versions prior to 4.2.16; MongoDB Server v4.4 versions prior to 4.4.9.","status":"published","published":"2021-12-15T12:30:10.405Z","modified":"2024-09-16T17:23:58.888Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:32:55.564736Z"}],"euvd":[{"id":"EUVD-2021-7750","description":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.27; MongoDB Server v4.2 versions prior to 4.2.16; MongoDB Server v4.4 versions prior to 4.4.9.","status":"published","published":"2021-12-15T12:30:10Z","modified":"2024-09-16T17:23:58Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T00:55:42.486621Z"}],"ghsa":[{"id":"GHSA-8jvf-jqg4-r6h2","title":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command...","description":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.25; MongoDB Server v4.2 versions prior to 4.2.14; MongoDB Server v4.4 versions prior to 4.4.6.","status":"published","published":"2021-12-16T00:02:12Z","modified":"2024-02-01T05:07:13Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:55:31.245778Z"}],"nvd":[{"id":"CVE-2021-20330","description":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.27; MongoDB Server v4.2 versions prior to 4.2.16; MongoDB Server v4.4 versions prior to 4.4.9.","status":"published","published":"2021-12-15T13:15:07.633Z","modified":"2026-06-17T03:33:41.2Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:07:02.189991Z"}],"osv":[{"id":"CVE-2021-20330","description":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.27; MongoDB Server v4.2 versions prior to 4.2.16; MongoDB Server v4.4 versions prior to 4.4.9.","status":"published","published":"2021-12-15T13:15:07.633Z","modified":"2026-10-24T14:51:05.675733769Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:18.004149Z"},{"id":"UBUNTU-CVE-2021-20330","description":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.27; MongoDB Server v4.2 versions prior to 4.2.16; MongoDB Server v4.4 versions prior to 4.4.9.","status":"withdrawn","published":"2021-12-15T13:15:00Z","modified":"2026-02-19T19:27:11.748149Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:54:26.29421Z"},{"id":"BIT-mongodb-2021-20330","title":"Specific replication command with malformed oplog entries can crash secondaries","description":"An attacker with basic CRUD permissions on a replicated collection can run the applyOps command with specially malformed oplog entries, resulting in a potential denial of service on secondaries. This issue affects MongoDB Server v4.0 versions prior to 4.0.27; MongoDB Server v4.2 versions prior to 4.2.16; MongoDB Server v4.4 versions prior to 4.4.9.","status":"published","published":"2024-03-06T10:58:03.684Z","modified":"2026-09-08T08:46:34.685626742Z","updated_at":"2026-11-02T15:28:33.072289Z"}]}}