{"id":"GHSA-52mq-6jcv-j79x","summary":"User content sandbox can be confused into opening arbitrary documents","details":"### Impact\n\nThe user content sandbox can be abused to trick users into opening unexpected documents after several user interactions. The content can be opened with a `blob` origin from the Matrix client, so it is possible for a malicious document to access user messages and secrets.\n\n### Patches\n\nThis has been fixed by https://github.com/matrix-org/matrix-react-sdk/pull/5657, which is included in 3.15.0.\n\n### Workarounds\n\nThere are no known workarounds.","aliases":["CVE-2021-21320"],"modified":"2026-05-07T05:00:33.122950900Z","published":"2021-03-03T02:23:56Z","database_specific":{"nvd_published_at":"2021-03-02T03:15:00Z","cwe_ids":["CWE-345"],"severity":"LOW","github_reviewed":true,"github_reviewed_at":"2021-03-02T02:47:04Z"},"references":[{"type":"WEB","url":"https://github.com/matrix-org/matrix-react-sdk/security/advisories/GHSA-52mq-6jcv-j79x"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21320"},{"type":"WEB","url":"https://github.com/matrix-org/matrix-react-sdk/pull/5657"},{"type":"WEB","url":"https://github.com/matrix-org/matrix-react-sdk/commit/b386f0c73b95ecbb6ea7f8f79c6ff5171a8dedd1"},{"type":"WEB","url":"https://www.npmjs.com/package/matrix-react-sdk"}],"affected":[{"package":{"name":"matrix-react-sdk","ecosystem":"npm","purl":"pkg:npm/matrix-react-sdk"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.15.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/03/GHSA-52mq-6jcv-j79x/GHSA-52mq-6jcv-j79x.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N"}]}