CVE-2026-28227
Authorization Bypass in Discourse Allows TL4 Users Staff-Only Posting
Publication date: 2026-02-26
Last updated on: 2026-03-02
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| discourse | discourse | to 2025.12.2 (exc) |
| discourse | discourse | From 2026.1.0 (inc) to 2026.1.1 (exc) |
| discourse | discourse | 2026.2.0 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-863 | The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability affects the Discourse open source discussion platform. Before certain fixed versions (2025.12.2, 2026.1.1, and 2026.2.0), users with TL4 privileges could publish topics into staff-only categories by using the `publish_to_category` topic timer feature. This action bypassed the normal authorization checks that should restrict access to staff-only categories.
How can this vulnerability impact me? :
The vulnerability allows TL4 users to publish content into staff-only categories without proper authorization. This could lead to unauthorized access or exposure of sensitive or restricted discussions intended only for staff members, potentially compromising confidentiality within the platform.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade your Discourse installation to one of the patched versions: 2025.12.2, 2026.1.1, or 2026.2.0.
No known workarounds are available, so applying the update is the recommended immediate step.