Improper access control in Discourse - CVE-2026-28227
Published: July 1, 2026
Vulnerability identifier: #VU136497
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-28227
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Civilized Discourse Construction Kit, Inc.
Affected software:
Discourse
Discourse
Detailed vulnerability description
The vulnerability allows a remote user to bypass authorization checks and create topics in staff-only categories.
The vulnerability exists due to improper access control in the `publish_to_category` topic timer when publishing topics into staff-only categories. A remote user can use the `publish_to_category` topic timer to bypass authorization checks and create topics in staff-only categories.
The issue affects TL4 users.
How to mitigate CVE-2026-28227
Install security update from vendor's website.