CVE-2026-47733: medium-severity vulnerability in RocketChat Rocket.Chat
Rocket.Chat: Missing URL protocol sanitization in ImageElement allows javascript: URLs in markdown images
Published · Updated
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.4epss 0.2%
exploitation probability
0.2%top 93% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
Affected products
RocketChat · Rocket.ChatRelated CVEs — RocketChat Rocket.Chat
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