{"id":"CVE-2021-21320","aliases":["EUVD-2021-0602","GHSA-52mq-6jcv-j79x"],"status":"published","title":"User content sandbox can be confused into opening arbitrary documents","description":"matrix-react-sdk is an npm package which is a Matrix SDK for React Javascript. In matrix-react-sdk before version 3.15.0, the user content sandbox can be abused to trick users into opening unexpected documents. The content is opened with a `blob` origin that cannot access Matrix user data, so messages and secrets are not at risk. This has been fixed in version 3.15.0.","severity":{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00922,"percentile":0.60805,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-345"],"published":"2021-03-02T02:45:16Z","modified":"2026-10-20T10:53:33Z","fixes":[{"ecosystem":"npm","package":"matrix-react-sdk","fixed_in":["3.15.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"matrix-react-sdk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.15.0"}]}]},{"source":"osv","ecosystem":"npm","package":"matrix-react-sdk","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.15.0"}]}]}],"products":[{"vendor":"matrix-org","product":"matrix-react-sdk"},{"vendor":"matrix-react-sdk_project","product":"matrix-react-sdk"}],"references":[{"url":"https://github.com/matrix-org/matrix-react-sdk/security/advisories/GHSA-52mq-6jcv-j79x","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://github.com/matrix-org/matrix-react-sdk/pull/5657","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/matrix-org/matrix-react-sdk/commit/b386f0c73b95ecbb6ea7f8f79c6ff5171a8dedd1","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://www.npmjs.com/package/matrix-react-sdk","tags":["x_refsource_MISC","x_transferred","Product","Third Party Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21320","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-52mq-6jcv-j79x"}],"sources":{"cve":[{"id":"CVE-2021-21320","title":"User content sandbox can be confused into opening arbitrary documents","description":"matrix-react-sdk is an npm package which is a Matrix SDK for React Javascript. In matrix-react-sdk before version 3.15.0, the user content sandbox can be abused to trick users into opening unexpected documents. The content is opened with a `blob` origin that cannot access Matrix user data, so messages and secrets are not at risk. This has been fixed in version 3.15.0.","status":"published","published":"2021-03-02T02:45:16Z","modified":"2024-08-03T18:09:15.273Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-345"],"updated_at":"2026-11-02T14:33:00.137099Z"}],"euvd":[{"id":"EUVD-2021-0602","description":"matrix-react-sdk is an npm package which is a Matrix SDK for React Javascript. In matrix-react-sdk before version 3.15.0, the user content sandbox can be abused to trick users into opening unexpected documents. The content is opened with a `blob` origin that cannot access Matrix user data, so messages and secrets are not at risk. This has been fixed in version 3.15.0.","status":"published","published":"2021-03-02T02:45:16Z","modified":"2024-08-03T18:09:15Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"updated_at":"2026-11-03T03:25:06.913643Z"}],"ghsa":[{"id":"GHSA-52mq-6jcv-j79x","title":"User content sandbox can be confused into opening arbitrary documents","description":"### 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.","status":"published","published":"2021-03-03T02:23:56Z","modified":"2023-02-01T05:05:16Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-345"],"updated_at":"2026-11-02T14:36:33.613868Z"}],"nvd":[{"id":"CVE-2021-21320","description":"matrix-react-sdk is an npm package which is a Matrix SDK for React Javascript. In matrix-react-sdk before version 3.15.0, the user content sandbox can be abused to trick users into opening unexpected documents. The content is opened with a `blob` origin that cannot access Matrix user data, so messages and secrets are not at risk. This has been fixed in version 3.15.0.","status":"published","published":"2021-03-02T03:15:13.213Z","modified":"2026-06-17T03:35:17.443Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-345"],"updated_at":"2026-11-02T14:06:50.399901Z"}],"osv":[{"id":"CVE-2021-21320","description":"matrix-react-sdk is an npm package which is a Matrix SDK for React Javascript. In matrix-react-sdk before version 3.15.0, the user content sandbox can be abused to trick users into opening unexpected documents. The content is opened with a `blob` origin that cannot access Matrix user data, so messages and secrets are not at risk. This has been fixed in version 3.15.0.","status":"published","published":"2021-03-02T03:15:13.213Z","modified":"2026-10-20T10:53:33.513937893Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:18.004149Z"},{"id":"GHSA-52mq-6jcv-j79x","title":"User content sandbox can be confused into opening arbitrary documents","description":"### 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.","status":"published","published":"2021-03-03T02:23:56Z","modified":"2026-07-08T06:28:20.267888512Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-345"],"updated_at":"2026-11-02T15:46:37.864461Z"}]}}