Discourse is an open-source discussion platform. Prior to version 3.2.3 on the `stable` branch and version 3.3.0.beta3 on the `tests-passed` branch, Oneboxing against a carefully crafted malicious URL can reduce the availability of a Discourse instance. The problem has been patched in version 3.2.3 on the `stable` branch and version 3.3.0.beta3 on the `tests-passed` branch. There are no known workarounds available for this vulnerability.

Missing Authorization vulnerability in Discourse WP Discourse.This issue affects WP Discourse: from n/a through 2.5.1.

Discourse-reactions is a plugin that allows user to add their reactions to the post. When whispers are enabled on a site via `whispers_allowed_groups` and reactions are made on whispers on public topics, the contents of the whisper and the reaction data are shown on the `/u/:username/activity/reactions` endpoint.

Discourse is an open source platform for community discussion. In affected versions an attacker can learn that secret categories exist when they have backgrounds set. The issue is patched in the latest stable, beta and tests-passed version of Discourse. Users are advised to upgrade. Users unable to upgrade should temporarily remove category backgrounds.

Discourse is an open source platform for community discussion. In affected versions the endpoints for suspending users, silencing users and exporting CSV files weren't enforcing limits on the sizes of the parameters that they accept. This could lead to excessive resource consumption which could render an instance inoperable. A site could be disrupted by either a malicious moderator on the same site or a malicious staff member on another site in the same multisite cluster. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Discourse is an open source platform for community discussion. In affected versions users that are allowed to invite others can inject arbitrarily large data in parameters used in the invite route. The problem has been patched in the latest version of Discourse. Users are advised to upgrade. Users unable to upgrade should disable invites or restrict access to them using the `invite allowed groups` site setting.

Discourse is an open source platform for community discussion. Without a rate limit on the POST /uploads endpoint, it makes it easier for an attacker to carry out a DoS attack on the server since creating an upload can be a resource intensive process. Do note that the impact varies from site to site as various site settings like `max_image_size_kb`, `max_attachment_size_kb` and `max_image_megapixels` will determine the amount of resources used when creating an upload. The issue is patched in the latest stable, beta and tests-passed version of Discourse. Users are advised to upgrade. Users unable to upgrade should reduce `max_image_size_kb`, `max_attachment_size_kb` and `max_image_megapixels` as smaller uploads require less resources to process. Alternatively, `client_max_body_size` can be reduced in Nginx to prevent large uploads from reaching the server.

Discourse is an open source platform for community discussion. In affected versions an attacker can learn that a secret subcategory exists under a public category which has no public subcategories. The issue is patched in the latest stable, beta and tests-passed version of Discourse. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Discourse Calendar adds the ability to create a dynamic calendar in the first post of a topic on the open-source discussion platform Discourse. Prior to version 0.4, event invitees created in topics in private categories or PMs (private messages) can be retrieved by anyone, even if they're not logged in. This problem is resolved in version 0.4 of the discourse-calendar plugin. While no known workaround is available, putting the site behind `login_required` will disallow this endpoint to be used by anonymous users, but logged in users can still get the list of invitees in the private topics.

discourse-ai is the AI plugin for the open-source discussion platform Discourse. Prior to commit 94ba0dadc2cf38e8f81c3936974c167219878edd, interactions with different AI services are vulnerable to admin-initiated SSRF attacks. Versions of the plugin that include commit 94ba0dadc2cf38e8f81c3936974c167219878edd contain a patch. As a workaround, one may disable the discourse-ai plugin.