CVE-2026-47733

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account, but needs a user to act. Limited direct impact.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-24 21:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-25 22:10 UTC Last updatedMost recent change to the record

Details

Published

2026-06-24 21:16 UTC

Last modified

2026-10-25 22:10 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-79 · Cross-site scripting

Record status

Deferred

Attack profile CVSS 3.1 · 4.4

Attack vector

Network

Complexity

High

Privileges needed

Low

User interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None