Discourse: Chat MessageBus delivers read-restricted messages to unauthorized users
Discourse is an open-source discussion platform. Prior to 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9, MessageBus audience calculation could deliver messages from a read-restricted category chat channel to an authenticated user who could view the category but was not allowed to use Chat under the site's group restrictions. The publication path bounded events by category visibility without also enforcing Chat eligibility, exposing live and recent message content available in the MessageBus backlog. The issue does not permit retrieval of the channel's full history through the Chat API and does not permit message creation or modification. This issue is fixed in versions 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9.
CVE-2026-91156
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-2026-91156
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": "< 2026.1.9"
},
{
"status": "affected",
"version": ">= 2026.7.0-latest, < 2026.7.3"
},
{
"status": "affected",
"version": ">= 2026.8.0-latest, < 2026.8.1"
},
{
"status": "affected",
"version": ">= 2026.9.0-latest, < 2026.9.0"
}
]
}
]- Related CVEs
- CVE-2026-91156
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #22868 · Revision 1
- Added to Heist Feed
- Publisher date