EUVD-2026-13192

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-2026-27570 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-2026-27491 Discourse has a bypass of official warnings messages by non-staff users

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a type coercion issue in a post actions API endpoint allowed non-staff users to issue warnings to other users. Warnings are a staff-only moderation feature. The vulnerability required the...

EUVD-2026-13190

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a type coercion issue in a post actions API endpoint allowed non-staff users to issue warnings to other users. Warnings are a staff-only moderation feature. The vulnerability required the...

CVE-2026-27491 Discourse has a bypass of official warnings messages by non-staff users

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a type coercion issue in a post actions API endpoint allowed non-staff users to issue warnings to other users. Warnings are a staff-only moderation feature. The vulnerability required the...

CVE-2026-27491 Discourse has a bypass of official warnings messages by non-staff users

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a type coercion issue in a post actions API endpoint allowed non-staff users to issue warnings to other users. Warnings are a staff-only moderation feature. The vulnerability required the...

EUVD-2026-13188

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-2026-27454 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-2026-27454 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-2026-27454

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-2026-27454

Discourse before versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 allowed unauthorized access to hidden post revisions via GET /posts/:id.json?version=X because display_post called post.revert_to without verifying revision visibility or editor permissions. The root cause was missing authorizati...

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...

CVE-2026-27166

Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions...

EUVD-2026-13187

Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions...

CVE-2026-27166 Discourse vulnerable to HTML injection via prohibited iframe URLs

Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions...

CVE-2026-27166 Discourse vulnerable to HTML injection via prohibited iframe URLs

Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions...

CVE-2026-27166 Discourse vulnerable to HTML injection via prohibited iframe URLs

Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and 2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions...

CVE-2026-27934: Insertion of Sensitive Information Into Sent Data

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a lack of visibility checks with a user action API endpoint that results in disclosure of the title and post excerpt to unauthorized users, leading to information disclosure. Versions...