CVE-2026-28227
Received Received - Intake
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
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, TL4 users can publish topics into staff-only categories via the `publish_to_category` topic timer, bypassing authorization checks. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
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Meta Information
Published
2026-02-26
Last Modified
2026-03-02
Generated
2026-06-16
AI Q&A
2026-02-27
EPSS Evaluated
2026-06-14
NVD
CVE-2026-28227
EUVD
EUVD-2026-8901
Affected Vendors & Products
Showing 3 associated CPEs
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
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KEV
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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.
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Executive Summary

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.

Impact Analysis

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.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

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.

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