{"id":"CVE-2026-47733","aliases":["EUVD-2026-39089","GHSA-vvrf-fq54-q4pr"],"status":"published","title":"Rocket.Chat: Missing URL protocol sanitization in ImageElement allows javascript: URLs in markdown images","description":"Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.0, the ImageElement component in packages/gazzodown renders user-controlled src values directly into \u003ca href\u003e and \u003cimg src\u003e attributes without protocol sanitization. Unlike the analogous LinkSpan component — which uses sanitizeUrl to block javascript:, data:, and vbscript: protocols — ImageElement passes the raw URL through unchanged. An authenticated user can post a markdown image with a javascript: URL that, if clicked on an older browser, would execute arbitrary JavaScript in the viewer's session. This vulnerability is fixed in 8.5.0.","severity":{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00141,"percentile":0.03486,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-79"],"published":"2026-06-24T20:51:29Z","modified":"2026-10-28T02:31:04Z","products":[{"vendor":"rocket.chat","product":"rocket.chat"},{"vendor":"rocketchat","product":"rocket.chat"}],"references":[{"url":"https://github.com/RocketChat/Rocket.Chat/security/advisories/GHSA-vvrf-fq54-q4pr","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47733.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47733","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-47733","title":"Rocket.Chat: Missing URL protocol sanitization in ImageElement allows javascript: URLs in markdown images","description":"Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.0, the ImageElement component in packages/gazzodown renders user-controlled src values directly into \u003ca href\u003e and \u003cimg src\u003e attributes without protocol sanitization. Unlike the analogous LinkSpan component — which uses sanitizeUrl to block javascript:, data:, and vbscript: protocols — ImageElement passes the raw URL through unchanged. An authenticated user can post a markdown image with a javascript: URL that, if clicked on an older browser, would execute arbitrary JavaScript in the viewer's session. This vulnerability is fixed in 8.5.0.","status":"published","published":"2026-06-24T20:51:29.245Z","modified":"2026-06-25T14:46:51.318Z","cvss":[{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T13:36:40.478484Z"}],"euvd":[{"id":"EUVD-2026-39089","description":"Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.0, the ImageElement component in packages/gazzodown renders user-controlled src values directly into \u003ca href\u003e and \u003cimg src\u003e attributes without protocol sanitization. Unlike the analogous LinkSpan component — which uses sanitizeUrl to block javascript:, data:, and vbscript: protocols — ImageElement passes the raw URL through unchanged. An authenticated user can post a markdown image with a javascript: URL that, if clicked on an older browser, would execute arbitrary JavaScript in the viewer's session. This vulnerability is fixed in 8.5.0.","status":"published","published":"2026-06-24T20:51:29Z","modified":"2026-06-25T14:46:51Z","cvss":[{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T18:20:25.700423Z"}],"nvd":[{"id":"CVE-2026-47733","description":"Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.0, the ImageElement component in packages/gazzodown renders user-controlled src values directly into \u003ca href\u003e and \u003cimg src\u003e attributes without protocol sanitization. Unlike the analogous LinkSpan component — which uses sanitizeUrl to block javascript:, data:, and vbscript: protocols — ImageElement passes the raw URL through unchanged. An authenticated user can post a markdown image with a javascript: URL that, if clicked on an older browser, would execute arbitrary JavaScript in the viewer's session. This vulnerability is fixed in 8.5.0.","status":"published","published":"2026-06-24T21:16:54.477Z","modified":"2026-10-25T22:10:00.15Z","cvss":[{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:25.67873Z"}],"osv":[{"id":"CVE-2026-47733","title":"Rocket.Chat: Missing URL protocol sanitization in ImageElement allows javascript: URLs in markdown images","description":"Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.0, the ImageElement component in packages/gazzodown renders user-controlled src values directly into \u003ca href\u003e and \u003cimg src\u003e attributes without protocol sanitization. Unlike the analogous LinkSpan component — which uses sanitizeUrl to block javascript:, data:, and vbscript: protocols — ImageElement passes the raw URL through unchanged. An authenticated user can post a markdown image with a javascript: URL that, if clicked on an older browser, would execute arbitrary JavaScript in the viewer's session. This vulnerability is fixed in 8.5.0.","status":"published","published":"2026-06-24T20:51:29.245Z","modified":"2026-10-28T02:31:04.800612686Z","cvss":[{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:06.231145Z"}]}}