Discourse Calendar adds the ability to create a dynamic calendar in the first post of a topic on Discourse. Uninvited users are able to gain access to private events by crafting a request to update their attendance. This problem is resolved in commit dfc4fa15f340189f177a1d1ab2cc94ffed3c1190. As a workaround, one may use post visibility to limit access.

`discourse-microsoft-auth` is a plugin that enables authentication via Microsoft. On sites with the `discourse-microsoft-auth` plugin enabled, an attack can potentially take control of a victim's Discourse account. Sites that have configured their application's account type to any options other than `Accounts in this organizational directory only (O365 only - Single tenant)` are vulnerable. This vulnerability has been patched in commit c40665f44509724b64938c85def9fb2e79f62ec8 of `discourse-microsoft-auth`. A `microsoft_auth:revoke` rake task has also been added which will deactivate and log out all users that have connected their accounts to Microsoft. User API keys as well as API keys created by those users will also be revoked. The rake task will also remove the connection records to Microsoft for those users. This will allow affected users to re-verify their account emails as well as reconnect their Discourse account to Microsoft for authentication. As a workaround, disable the `di…

discourse-group-membership-ip-block is a discourse plugin that adds support for adding users to groups based on their IP address. discourse-group-membership-ip-block was sending all group custom fields to the client, including group custom fields from other plugins which may expect their custom fields to remain secret.

Discourse is an open-source discussion platform. Improperly sanitized user input could lead to an XSS vulnerability in some situations. This vulnerability only affects Discourse instances which have disabled the default Content Security Policy. The vulnerability is patched in 3.1.5 and 3.2.0.beta5. As a workaround, ensure Content Security Policy is enabled and does not include `unsafe-inline`.

Discourse is a platform for community discussion. For fields that are client editable, limits on sizes are not imposed. This allows a malicious actor to cause a Discourse instance to use excessive disk space and also often excessive bandwidth. The issue is patched 3.1.4 and 3.2.0.beta4.

Discourse is a platform for community discussion. Under very specific circumstances, secure upload URLs associated with posts can be accessed by guest users even when login is required. This vulnerability has been patched in 3.2.0.beta4 and 3.1.4.

Discourse-reactions is a plugin that allows user to add their reactions to the post. Data about a user's reaction notifications could be exposed. This vulnerability was patched in commit 2c26939.

Discourse is a platform for community discussion. The message serializer uses the full list of expanded chat mentions (@all and @here) which can lead to a very long array of users. This issue was patched in versions 3.1.4 and beta 3.2.0.beta5.

Discourse is an open source platform for community discussion. Prior to version 3.1.3 of the `stable` branch and version 3.2.0.beta3 of the `beta` and `tests-passed` branches, the embedding feature is susceptible to server side request forgery. The issue is patched in version 3.1.3 of the `stable` branch and version 3.2.0.beta3 of the `beta` and `tests-passed` branches. As a workaround, disable the Embedding feature.

Discourse is an open source platform for community discussion. In versions 3.1.0 through 3.1.2 of the `stable` branch and versions 3.1.0,beta6 through 3.2.0.beta2 of the `beta` and `tests-passed` branches, Redis memory can be depleted by crafting a site with an abnormally long favicon URL and drafting multiple posts which Onebox it. The issue is patched in version 3.1.3 of the `stable` branch and version 3.2.0.beta3 of the `beta` and `tests-passed` branches. There are no known workarounds.