Discourse: Chat MessageBus delivers read-restricted messages to unauthorized users
Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an attacker-controlled event handler. An authenticated user with default trust-level posting privileges could store the crafted placeholder in a post. When another user opened the post and clicked the video play overlay, the handler could execute arbitrary JavaScript in the viewer's session. Default Content Security Policy settings block inline event handlers, but instances with CSP disabled or relaxed could allow the script to read page content and make authenticated requests as the viewer. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.
CVE-2026-91122
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-91122
discourse
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "discourse",
"product": "discourse",
"versions": [
{
"status": "affected",
"version": "< 2026.8.0"
},
{
"status": "affected",
"version": ">= 2026.7.0-latest, < 2026.7.2"
},
{
"status": "affected",
"version": ">= 2026.6.0-latest, < 2026.6.3"
},
{
"status": "affected",
"version": ">= 2026.1.0-latest, < 2026.1.8"
}
]
}
]- Related CVEs
- CVE-2026-91122
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #1815 · Revision 1
- Added to Heist Feed
- Publisher date