CVE-2026-47733Rocket.Chat: Missing URL protocol sanitization in ImageElement allows javascript: URLs in markdown images
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 4.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Jun 25, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
RocketChat Rocket.Chat rocketchat:rocket.chat (from the name) | before 8.5.0 | CNA record |
References
- https://github.com/RocketChat/Rocket.Chat/security/advisories/GHSA-vvrf-fq54-q4prx-refsource-confirm
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.