CVE-2026-72724
Discourse: Private Chat Threat Message Disclosure via Chat Onebox Channel/Threat ID Mismatch
- State
- Published
- Severity
- 4.3 Medium
- Published
- Aug 10, 2026
- Updated
- Aug 11, 2026
- Reserved
- Aug 10, 2026
Description
Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, plugins/chat/lib/chat/onebox_handler.rb resolves Chat::Thread by route thread_id independently of the route channel_id before checking whether the user can preview the selected chat channel. An authenticated user can pair a public channel ID with a private thread ID in a /onebox.json request and obtain private thread message content. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 4.3 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N | GitHub_M |
Weaknesses
- CWE-639 Authorization Bypass Through User-Controlled Key
Affected Products
| Product | Versions |
|---|---|
discoursediscourse |
|
References
- https://github.com/discourse/discourse/security/advisories/GHSA-8g98-fvfc-9w48
- https://github.com/discourse/discourse/pull/42091
- https://github.com/discourse/discourse/pull/42092
- https://github.com/discourse/discourse/pull/42093
- https://github.com/discourse/discourse/pull/42094
- https://github.com/discourse/discourse/commit/1276d7032af8803956c74ae87ccfd976938dcd75
- https://github.com/discourse/discourse/commit/45ab6d54076de9ca4965888974d4416d5b48e83c
- https://github.com/discourse/discourse/commit/49efe1d7f098f2ce7301908815a211cc9248270f
- https://github.com/discourse/discourse/commit/dc54846f0754799591717b6018343e49524e41ce
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