Track vulnerabilities like this one. Sign up free to get alerted when software you use is affected.
4.3

Discourse: Users can see restricted topic titles through links

CVE-2026-72722 · published 2 months ago
Summary

Discourse, a discussion platform, had a security issue where users could see titles of private or restricted topics by submitting links to those topics. This has been fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0. Update to one of these fixed versions to prevent this issue.

What to do
  • Update discourse to version 2026.6.1.
Affected software
Ecosystem VendorProductAffected versions
– discourse discourse < 2026.1.6
Bitnami – discourse >= 2026.6.0, < 2026.6.1
Fix: upgrade to 2026.6.1
Original advisory text
Discourse: Duplicate lookup reveals restricted topic titles through canonicalized URLs
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.
References
Fix within
Internet-facing 60 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker partial control
Severity
4.3 Medium
Exploitation
<1% chance of attack within 30 days
Type
CWE-862Missing Authorization
Timeline
Published10 Aug 2026
Updated4 Nov 2026
First seen10 Aug 2026
Sources
CVE-2026-72722 · NVD
CVE-2026-72722 · MITRE
BIT-discourse-2026-72722 · OSV
GHSA-4fx9-5m29-83p4 · GHSA
CVE-2026-72722 · OSV
Track software like this
Free during beta