Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, unauthenticated users can determine whether a specific user is a member of a private group by observing changes in directory results when using the `exclude_groups` parameter. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch.
As a workaround, disable public access to the user directory via Admin → Settings → hide user profiles from public.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 3
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Discourse Discourse
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
|
2026.1.0
|
2026.1.2
|
|
Discourse Discourse
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
|
2026.2.0
|
2026.2.1
|
|
Discourse Discourse
cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*
|
— | — |