CVE-2026-47733
MEDIUM
MEDIUM
Priority: 0.01
BB Relevance:
39/100
Published: 2026-06-24
Modified: 2026-10-25
First seen: 2026-10-29
Status: active
Attack Surface
Network
Scope Change
CVSS Vector Breakdown
AV:
Network
AC:
High
PR:
Low
UI:
Required
S:
Changed
C:
Low
I:
Low
A:
None
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 <a href> and <img src> 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.