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-2026-27166

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...

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...

EUVD-2026-13194

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-2026-27740 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-2026-27740

Discourse (open-source discussion platform) is affected by CVE-2026-27740. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 are vulnerable to stored XSS caused by trusting raw output from an AI Large Language Model and rendering it with htmlSafe in the Review Queue without adequate san...

CVE-2026-27570

Discourse is vulnerable to stored XSS via the SharedAiConversation onebox. In affected versions before 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the onebox renders the conversation title into HTML without proper sanitization. A patch exists in 2026.3.0-latest.1, 2026.2.1, and 2026.1.2. The recom...

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...

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...

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...

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 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...