Discourse is an open source discussion platform. Prior to versions 3.5.3, 2025.11.1, and 2025.12.0, an attacker who knows part of a username can find the user and their full name via UI or API, even when enable_names is disabled. Versions 3.5.3, 2025.11.1, and 2025.12.0 contain a fix.
Weakness
When trying to keep information confidential, an attacker can often infer some of the information by using statistics.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Discourse | Discourse | * | 3.5.3 (excluding) |
| Discourse | Discourse | 2025.11.0 (including) | 2025.11.0 (including) |
| Discourse | Discourse | 2025.12.0 (including) | 2025.12.0 (including) |
Potential Mitigations
References
- https://github.com/discourse/discourse/commit/1cb45b8b287597085e3514596ffb1d9b41938f81
- https://github.com/discourse/discourse/commit/6192f55629624925595dae14364fd86cac0f09df
- https://github.com/discourse/discourse/commit/e936a523b5900a9d866d23ea3da904ba12bb0fb2
- https://github.com/discourse/discourse/security/advisories/GHSA-c59w-jwx7-34v4