Discourse

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, staged user custom fields and username are exposed on public invite pages without email verification. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-04-03T21:27:59.837Z
Updated: 2026-04-07T14:17:59.649Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a non-staff user with elevated group membership could access deleted posts belonging to any user due to an overly broad authorization check on the deleted posts index endpoint. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-20T23:21:20.877Z
Updated: 2026-03-25T13:42:54.320Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an unauthenticated attacker can cause a legitimate Discourse authorization page to display an attacker-controlled domain, facilitating social engineering attacks against users. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-20T23:20:03.149Z
Updated: 2026-03-23T21:41:14.354Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, users with tag-editing permissions could edit and create synonyms for tags hidden in restricted tag groups, even if they lacked visibility into those tags. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-20T23:14:57.484Z
Updated: 2026-03-24T15:30:29.255Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, unauthenticated users can determine whether a specific user is a member of a private group by observing changes in directory results when using the `exclude_groups` parameter. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, disable public access to the user directory via Admin → Settings → hide user profiles from public.

Published: 2026-03-20T23:12:30.489Z
Updated: 2026-03-23T16:48:49.363Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an attacker can grant access to a private message topic through invites even after they lose access to that PM. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-20T23:08:11.929Z
Updated: 2026-03-25T13:43:16.900Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, staff can modify any user's group notification level. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-20T23:06:21.734Z
Updated: 2026-03-23T21:41:22.620Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `ip_address` of a flagged user is exposed to any user who can access the review queue, including users who should not be able to see IP addresses. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-20T23:04:45.477Z
Updated: 2026-03-24T02:10:31.793Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authenticated moderator-level user could retrieve post content, topic titles, and usernames from categories they were not authorized to view. Insufficient access controls on a sentiment analytics endpoint allowed category permission boundaries to be bypassed. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:42:15.870Z
Updated: 2026-04-03T16:21:37.890Z

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a potential stored XSS in topic titles for the solved posts stream. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.

Published: 2026-03-20T22:58:14.546Z
Updated: 2026-03-24T18:03:07.240Z

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have two authorization issues in the chat direct message API. First, when creating a direct message channel or adding users to an existing one, the `target_groups` parameter was passed directly to the user resolution query without checking group or member visibility for the acting user. An authenticated chat user could craft an API request with a known private/hidden group name and receive a channel containing that group's members, leaking their identities. Second, `can_chat?` only checked group membership, not the `chat_enabled` user preference. A chat-disabled user could create or query DM channels between other users via the direct messages API, potentially exposing private `last_message` content from the serialized channel response. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T21:57:27.176Z
Updated: 2026-03-20T16:11:14.726Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, moderators were able to see the first 40 characters of post edits in PMs and private categories. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T22:35:14.367Z
Updated: 2026-03-20T20:08:36.220Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the discourse-graphviz plugin contains a stored cross-site scripting (XSS) vulnerability that allows authenticated users to inject malicious JavaScript code through DOT graph definitions. For instances with CSP disabled only. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, disable the graphviz plugin, upgrade to a patched version, or enable a content security policy.

Published: 2026-03-19T22:33:19.328Z
Updated: 2026-03-20T16:40:49.907Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the Post Edits admin report (/admin/reports/post_edits) leaked the first 40 characters of raw post content from private messages and secure categories to moderators who shouldn't have access. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T22:06:06.572Z
Updated: 2026-03-20T18:36:24.612Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `allowed_spam_host_domains` check used `String#end_with?` without domain boundary validation, allowing domains like `attacker-example.com` to bypass spam protection when `example.com` was allowlisted. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 require exact match or proper subdomain match (preceded by `.`) to prevent suffix-based bypass of `newuser_spam_host_threshold`. No known workarounds are available.

Published: 2026-03-19T22:04:26.484Z
Updated: 2026-03-20T20:15:16.294Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the `/private-posts` endpoint did not apply post-type visibility filtering, allowing regular PM participants to see whisper posts in PM topics they had access to. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T22:01:42.387Z
Updated: 2026-03-20T18:10:20.981Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authorization bypass in the Category Chatables Controller show action allowed moderators to get information on hidden groups names and user count. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:42:00.882Z
Updated: 2026-04-01T18:34:16.767Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, moderators can create Zendesk tickets for topics they do not have access to view. This affects all forums that use the Zendesk plugin. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-20T22:56:06.423Z
Updated: 2026-03-24T02:08:54.073Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an authorization bypass vulnerability in hidden Solved topics may allow unauthorized users to accept or unaccept solutions. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, ensure only trusted users are part of the Site Setting for accept_all_solutions_allowed_groups.

Published: 2026-03-20T22:52:37.051Z
Updated: 2026-03-24T18:05:41.967Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, the group email settings test endpoint could be used to make the server initiate outbound connections to arbitrary hosts and ports. This could allow probing of internal network infrastructure. The endpoint was accessible to non-staff group owners. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:41:44.893Z
Updated: 2026-04-01T13:47:00.577Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, the discourse-subscriptions plugin leaks stripe API keys across sites in a multisite cluster resulting in the potential for stripe related information to be leaked across sites within the same multisite cluster. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:38:59.916Z
Updated: 2026-04-03T16:16:18.969Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authenticated user can obtain shared draft topic titles by sending an inline onebox request with a category_id parameter matching the shared drafts category. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:41:20.559Z
Updated: 2026-04-01T18:33:42.891Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, non-staff users could access read receipt information for staff-only posts they weren't supposed to see. No post content was exposed, only metadata about who read the post and when. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:41:03.246Z
Updated: 2026-04-01T13:48:23.128Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, users who lost access to a topic (e.g., removed from a private category group) could still interact with polls in that topic, including voting and toggling poll status. No content was exposed, but users could modify poll state in topics they should no longer have access to. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:40:41.588Z
Updated: 2026-03-31T18:52:26.060Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, there is possible channel membership inference from chat user search without authorization. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:40:41.484Z
Updated: 2026-04-03T16:20:00.471Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, category group moderators could perform privileged actions on topics inside private categories they did not have read access to. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:40:17.212Z
Updated: 2026-04-01T18:06:54.206Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, when the hidden prioritize_full_name_in_ux site setting is enabled (defaults to false, requires console access to change), user and group display names are rendered without HTML escaping in several assignment-related UI paths. This allows users with assign permission to inject arbitrary HTML/JavaScript that executes in the browser of any user viewing an affected topic. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:40:05.155Z
Updated: 2026-04-01T13:48:54.473Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, updating a category description via API is not sanitizing the description string, which can lead to XSS attacks. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:39:48.771Z
Updated: 2026-03-31T18:52:31.983Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an attacker with the ability to create shared AI conversations could inject arbitrary HTML and JavaScript via crafted conversation titles. This payload would execute in the browser of any user viewing the onebox preview, potentially allowing session hijacking or unauthorized actions on behalf of the victim. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:39:38.318Z
Updated: 2026-04-03T16:18:12.209Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, moderators could export CSV data for admin-restricted reports, bypassing the report visibility restrictions. This could expose sensitive operational data intended only for admins. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:39:25.635Z
Updated: 2026-04-01T18:05:32.105Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, there is an Insecure Direct Object Reference (IDOR) vulnerability that allows any authenticated user to access metadata about AI personas, features, and LLM models by providing their identifiers. This information includes credit allocations and usage statistics which are not intended to be public. The attack is performed over the network, requires low privileges (any logged-in user), and results in a low impact on confidentiality with no impact on integrity or availability. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. To work around this issue, disable AI plugin or upgrade to a patched version.

Published: 2026-03-20T03:13:34.838Z
Updated: 2026-03-20T14:29:13.455Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, the enter action in StaticController reads the sso_destination_url cookie and redirects to it with allow_other_host: true without validating the destination URL. While this cookie is normally set during legitimate DiscourseConnect Provider flows with cryptographically validated SSO payloads, cookies are client-controlled and can be set by attackers. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-03-31T17:39:25.820Z
Updated: 2026-04-01T13:56:12.868Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, when a user has `hide_profile` enabled, their bio, location, and website were still exposed through the user onebox preview. An authenticated user could request a onebox for a hidden user's profile URL and receive their hidden profile fields (bio, location, website) in the response. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T21:52:24.531Z
Updated: 2026-03-20T18:38:21.818Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the ComposerController#mentions endpoint reveals hidden group membership to any authenticated user who can message the group. By supplying allowed_names referencing a hidden-membership group and probing arbitrary usernames, an attacker can infer membership based on whether user_reasons returns "private" for a given user. This bypasses group member-visibility controls. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. To work around this issue, restrict the messageable policy of any hidden-membership group to staff or group members only, so untrusted users cannot reach the vulnerable code path.

Published: 2026-03-20T03:10:43.213Z
Updated: 2026-03-20T17:18:59.947Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an authorization bypass in the poll plugin allowed authenticated users to vote on, remove votes from, or toggle the open/closed status of polls they did not have access to. By passing post_id as an array (e.g. post_id[]=&post_id[]=), the authorization check resolves to the accessible post while the poll lookup resolves to a different post's poll. This affects the vote, remove_vote, and toggle_status endpoints in DiscoursePoll::PollsController. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch.

Published: 2026-03-20T03:07:14.755Z
Updated: 2026-03-20T15:46:27.399Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a user could access another user's private activity due to insufficient authorization checks in the user actions endpoint. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch.

Published: 2026-03-20T03:02:27.060Z
Updated: 2026-03-20T14:29:38.615Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a moderator could exploit insufficient authorization checks to access metadata of posts they should not have permission to view. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch.

Published: 2026-03-20T02:59:13.574Z
Updated: 2026-03-20T18:08:26.590Z

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 allow a moderator to edit site policy documents (ToS, guidelines, privacy policy) that they are explicitly prohibited from modifying. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-20T02:55:58.300Z
Updated: 2026-03-21T02:54:32.524Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, users who do not belong to the allowed policy creation groups can create functional policy acceptance widgets in posts under the right conditions. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, disable the discourse-policy plugin by disabling the `policy_enabled` site setting.

Published: 2026-03-19T21:49:33.865Z
Updated: 2026-03-20T16:27:46.085Z

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a security flaw in the discourse-policy plugin which allowed a user with policy creation permission to gain membership access to any private/restricted groups. Once membership to a private/restricted group has been obtained, the user will be able to read private topics that only the group has access to. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, review all policies for the use of `add-users-to-group` and temporarily remove the attribute from the policy. Alternatively, disable the discourse-policy plugin by disabling the `policy_enabled` site setting.

Published: 2026-03-19T21:45:13.648Z
Updated: 2026-03-20T18:10:26.922Z

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a restriction bypass allows restricted post action counts to be disclosed to non-privileged users through a carefully crafted request. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T21:42:36.677Z
Updated: 2026-03-24T01:45:26.962Z

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a vulnerability in an API endpoint that discloses private topic metadata of admin users to moderator users even if the moderators do not have access to the private topics. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T21:33:38.459Z
Updated: 2026-03-20T16:28:35.052Z

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 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T21:17:43.369Z
Updated: 2026-03-20T18:53:53.212Z

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 interface without adequate sanitization. A malicious attacker can use valid Prompt Injection techniques to force the AI to return a malicious payload (e.g., tags). When a Staff member (Admin/Moderator) views the flagged post in the Review Queue, the payload executes. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, temporarily disable AI triage automation scripts.

Published: 2026-03-19T20:56:17.272Z
Updated: 2026-03-20T18:10:38.878Z

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 contain a patch. As a workaround, tighten access by changing the `ai_bot_public_sharing_allowed_groups` site setting.

Published: 2026-03-19T20:52:17.572Z
Updated: 2026-03-24T19:43:07.713Z

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 attacker to be a logged-in user and to send a specifically crafted request. No data exposure or privilege escalation beyond the ability to create unauthorized user warnings was possible. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Published: 2026-03-19T20:47:54.668Z
Updated: 2026-03-20T20:20:00.790Z

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an authorization bypass vulnerability allows unauthenticated or unauthorized users to view hidden (staff-only) tags and its associated data. All Discourse instances with tagging enabled and staff-only tag groups configured are impacted. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Published: 2026-04-03T21:27:12.156Z
Updated: 2026-04-07T14:18:35.689Z

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 display_post method called post.revert_to directly without verifying whether the revision was hidden or if the user had permission to view edit history. This meant hidden revisions (intentionally concealed by staff) could be read by any user by simply enumerating version numbers. Starting in versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, Discourse looks up the PostRevision and call guardian.ensure_can_see! before reverting, consistent with how the /posts/:id/revisions/:revision endpoint already authorizes access. No known workarounds are available.

Published: 2026-03-19T20:39:28.350Z
Updated: 2026-03-20T17:10:14.076Z

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 2026.3.0-latest.1, 2026.2.1 and 2026.1.2. To workaround this issue, remove Codepen from the list of allowed iframes.

Published: 2026-03-19T20:29:22.570Z
Updated: 2026-03-21T03:31:58.296Z