CVE-2026-47733 (GCVE-0-2026-47733)

Vulnerability from cvelistv5 – Published: 2026-06-24 20:51 – Updated: 2026-06-25 14:46
VLAI
Title
Rocket.Chat: Missing URL protocol sanitization in ImageElement allows javascript: URLs in markdown images
Summary
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.
Severity
4.4 (Medium)
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-25 14:46 UTC
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
GitHub_M CNA
References
Impacted products
Vendor Product Version
RocketChat Rocket.Chat Affected: < 8.5.0
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