CVE-2026-72722 Discourse: Duplicate lookup reveals restricted topic titles through canonicalized URLs
Authenticated users can view titles of restricted topics via duplicate lookup responses, exposing private information.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72722?
CVE-2026-72722 is a medium-severity vulnerability in discourse, published on 10 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, TopicLink.extract_from, TopicLink.ensure_entry_for, and TopicLink.duplicate_lookup do not consistently enforce Guardian.can_see? checks when processing internal links. An authenticated user can submit links to restricted topics, private messages, or hidden posts and receive canonicalized slugs or titles in the composer_messages duplicate_lookup response even though the targets are not visible to that user. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Weakness: CWE-862
Which versions are affected by CVE-2026-72722?
1 open source package ship an affected version, including discourse.
| Package | Affected | Fixed in |
|---|---|---|
discourse Bitnami | All versions | 2026.1.6, 2026.5.2, 2026.6.1 |
How do I fix CVE-2026-72722?
Upgrade discourse to a fixed version for your release line: 2026.1.6, 2026.5.2 or 2026.6.1.
Is CVE-2026-72722 being exploited?
There is no known exploitation of CVE-2026-72722 in the wild and no public exploit code.
Sources
Also known as BIT-discourse-2026-72722, GHSA-4fx9-5m29-83p4.