CVE-2026-27740 Discourse has Stored XSS in AI Triage Automation

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a cross-site scripting vulnerability that arises because the system trusts the raw output from an AI Large Language Model LLM and renders it using htmlSafe in the Review Queue interfa...

CVE-2026-27570 Discourse Vulnerable to Stored XSS via Shared AI Conversation Onebox

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the onebox method in the SharedAiConversation model renders the conversation title directly into HTML without proper sanitization. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 conta...

CVE-2026-27491

Discourse contains a type coercion vulnerability in the post actions API that allowed non-staff, logged-in users to issue warnings to other users. Affected versions are 2026.3.0-latest.1, 2026.2.1, and 2026.1.2; patch versions are also noted. The underlying cause is a type coercion issue in the p...

CVE-2026-27454 Discourse has check revision visibility on posts endpoint

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, requesting /posts/:id.json?version=X bypassed authorization checks on post revisions. The displaypost method called post.revertto directly without verifying whether the revision was hidde...

CVE-2026-27166

CVE-2026-27166 (Discourse) : Vulnerability in the default Codepen iframe handling where insufficient cleanup allowed an attacker to cause a user to change the main page URL. Affected software: Discourse before versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2. Root cause: improper filtering/clea...

PT-2026-26425

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.3.0-latest.1 Discourse versions prior to 2026.2.1 Discourse versions prior to 2026.1.2 Description Discourse is an open-source discussion platform. The allowed spam host domains check utilized Stringend with?...

PT-2026-26359

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.3.0-latest.1 Discourse versions prior to 2026.2.1 Discourse versions prior to 2026.1.2 Description Discourse is an open-source discussion platform. A type coercion issue exists in a post actions API endpoint...

PT-2026-26360

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.3.0-latest.1 Discourse versions prior to 2026.2.1 Discourse versions prior to 2026.1.2 Description Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, t...

PT-2026-26377

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.3.0-latest.1 Discourse versions prior to 2026.2.1 Discourse versions prior to 2026.1.2 Description Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a...

PT-2026-26371

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.3.0-latest.1 Discourse versions prior to 2026.2.1 Discourse versions prior to 2026.1.2 Description Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2...

PT-2026-26370

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.3.0-latest.1 Discourse versions prior to 2026.2.1 Discourse versions prior to 2026.1.2 Description Discourse, an open-source discussion platform, is affected by an information disclosure issue. A lack of...

PT-2026-26423

Name of the Vulnerable Software and Affected Versions Discourse versions prior to 2026.3.0-latest.1 Discourse versions prior to 2026.2.1 Discourse versions prior to 2026.1.2 Description Discourse is an open-source discussion platform. When a user has hide profile enabled, their bio, location, and...

BIT-DISCOURSE-2026-26979 Discourse: TL4 users are able to change status of restricted topics

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, TL4 users are able to close, archive and pin topics in private categories they don't have access to. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available...

CVE-2026-28219

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, an improper authorization check in the topic management logic allows authenticated users to modify privileged attributes of their topics. By manipulating specific parameters in a PUT or POST...

CVE-2026-26078

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, when the patreonwebhooksecret site setting is blank, an attacker can forge valid webhook signatures by computing an HMAC-MD5 with an empty string as the key. Since the request body is known to th...

CVE-2026-27154

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: displaynameonposts = true; and prioritizeusernameinux = false. Editing a post of a malicious user would trigger ...

EUVD-2026-8901

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 publishtocategory topic timer, bypassing authorization checks. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known...

EUVD-2026-8900

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, an improper authorization check in the topic management logic allows authenticated users to modify privileged attributes of their topics. By manipulating specific parameters in a PUT or POST...

CVE-2026-28219 Privilege Escalation via Mass Assignment Allows Regular Users to Set Topics as Global Banners

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, an improper authorization check in the topic management logic allows authenticated users to modify privileged attributes of their topics. By manipulating specific parameters in a PUT or POST...

EUVD-2026-8895

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: displaynameonposts = true; and prioritizeusernameinux = false. Editing a post of a malicious user would trigger ...