Vulnerabilities (CVE)

Discourse is an open source platform for community discussion. Tags that are normally private are showing in metadata. This affects any site running the `tests-passed` or `beta` branches >= 3.1.0.beta2. The issue is patched in the latest `beta` and `tests-passed` version of Discourse.

Discourse is an open-source discussion platform. Prior to version 3.0.1 of the `stable` branch and version 3.1.0.beta2 of the `beta` and `tests-passed` branches, a maliciously crafted URL can be included in a user's full name field to to carry out cross-site scripting attacks on sites with a disabled or overly permissive CSP (Content Security Policy). Discourse's default CSP prevents this vulnerability. The vulnerability is patched in version 3.0.1 of the `stable` branch and version 3.1.0.beta2 ... Discourse is an open-source discussion platform. Prior to version 3.0.1 of the `stable` branch and version 3.1.0.beta2 of the `beta` and `tests-passed` branches, a maliciously crafted URL can be included in a user's full name field to to carry out cross-site scripting attacks on sites with a disabled or overly permissive CSP (Content Security Policy). Discourse's default CSP prevents this vulnerability. The vulnerability is patched in version 3.0.1 of the `stable` branch and version 3.1.0.beta2 of the `beta` and `tests-passed` branches. As a workaround, enable and/or restore your site's CSP to the default one provided with Discourse.

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Discourse is an open source discussion platform. In affected versions a malicious user can cause a regular expression denial of service using a carefully crafted git URL. 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 issue.

Discourse is an open-source messaging platform. In versions 3.0.1 and prior on the `stable` branch and versions 3.1.0.beta2 and prior on the `beta` and `tests-passed` branches, the count of personal messages displayed for a tag is a count of all personal messages regardless of whether the personal message is visible to a given user. As a result, any users can technically poll a sensitive tag to determine if a new personal message is created even if the user does not have access to the personal m ... Discourse is an open-source messaging platform. In versions 3.0.1 and prior on the `stable` branch and versions 3.1.0.beta2 and prior on the `beta` and `tests-passed` branches, the count of personal messages displayed for a tag is a count of all personal messages regardless of whether the personal message is visible to a given user. As a result, any users can technically poll a sensitive tag to determine if a new personal message is created even if the user does not have access to the personal message. In the patched versions, the count of personal messages tagged with a given tag is hidden by default. To revert to the old behaviour of displaying the count of personal messages for a given tag, an admin may enable the `display_personal_messages_tag_counts` site setting.

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Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches, someone can use the `exclude_tag param` to filter out topics and deduce which ones were using a specific hidden tag. This affects any Discourse site using hidden tags in public categories. This issue is patched in version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches. As a workaround, sec ... Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches, someone can use the `exclude_tag param` to filter out topics and deduce which ones were using a specific hidden tag. This affects any Discourse site using hidden tags in public categories. This issue is patched in version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches. As a workaround, secure any categories that are using hidden tags, change any existing hidden tags to not include private data, or remove any hidden tags currently in use.

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Discourse is an open-source discussion platform. Prior to version 3.0.1 of the `stable` branch and version 3.1.0.beta2 of the `beta` and `tests-passed` branches, the count of topics displayed for a tag is a count of all regular topics regardless of whether the topic is in a read restricted category or not. As a result, any users can technically poll a sensitive tag to determine if a new topic is created in a category which the user does not have excess to. In version 3.0.1 of the `stable` bran ... Discourse is an open-source discussion platform. Prior to version 3.0.1 of the `stable` branch and version 3.1.0.beta2 of the `beta` and `tests-passed` branches, the count of topics displayed for a tag is a count of all regular topics regardless of whether the topic is in a read restricted category or not. As a result, any users can technically poll a sensitive tag to determine if a new topic is created in a category which the user does not have excess to. In version 3.0.1 of the `stable` branch and version 3.1.0.beta2 of the `beta` and `tests-passed` branches, the count of topics displayed for a tag defaults to only counting regular topics which are not in read restricted categories. Staff users will continue to see a count of all topics regardless of the topic's category read restrictions.

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Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches. There are no known workarounds.

Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and 3.1.0.beta2 on the `beta` and `tests-passed` branches, the contents of latest/top routes for restricted tags can be accessed by unauthorized users. This issue is patched in version 3.0.1 on the `stable` branch and 3.1.0.beta2 on the `beta` and `tests-passed` branches. There are no known workarounds.

Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and 3.1.0.beta2 on the `beta` and `tests-passed` branches, when submitting a membership request, there is no character limit for the reason provided with the request. This could potentially allow a user to flood the database with a large amount of data. However it is unlikely this could be used as part of a DoS attack, as the paths reading back the reasons are only available to administrators. Starting ... Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and 3.1.0.beta2 on the `beta` and `tests-passed` branches, when submitting a membership request, there is no character limit for the reason provided with the request. This could potentially allow a user to flood the database with a large amount of data. However it is unlikely this could be used as part of a DoS attack, as the paths reading back the reasons are only available to administrators. Starting in version 3.0.1 on the `stable` branch and 3.1.0.beta2 on the `beta` and `tests-passed` branches, a limit of 280 characters has been introduced for membership requests.

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Discourse is an open source discussion platform. The embeddable comments can be exploited to create new topics as any user but without any clear title or content. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. As a workaround, disable embeddable comments by deleting all embeddable hosts.

Discourse is an open source platform for community discussion. Versions prior to 3.1.0.beta1 (beta) (tests-passed) are vulnerable to Allocation of Resources Without Limits. Users can create chat drafts of an unlimited length, which can cause a denial of service by generating an excessive load on the server. Additionally, an unlimited number of drafts were loaded when loading the user. This issue has been patched in version 2.1.0.beta1 (beta) and (tests-passed). Users should upgrade to the lates ... Discourse is an open source platform for community discussion. Versions prior to 3.1.0.beta1 (beta) (tests-passed) are vulnerable to Allocation of Resources Without Limits. Users can create chat drafts of an unlimited length, which can cause a denial of service by generating an excessive load on the server. Additionally, an unlimited number of drafts were loaded when loading the user. This issue has been patched in version 2.1.0.beta1 (beta) and (tests-passed). Users should upgrade to the latest version where a limit has been introduced. There are no workarounds available.

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Discourse is an open source platform for community discussion. Versions prior to 3.0.1 (stable), 3.1.0.beta2 (beta), and 3.1.0.beta2 (tests-passed) are subject to Allocation of Resources Without Limits or Throttling. As there is no limit on data contained in a draft, a malicious user can create an arbitrarily large draft, forcing the instance to a crawl. This issue is patched in versions 3.0.1 (stable), 3.1.0.beta2 (beta), and 3.1.0.beta2 (tests-passed). There are no workarounds.

Discourse is an open source platform for community discussion. Versions prior to 2.8.13 (stable), 3.0.0.beta16 (beta) and 3.0.0beta16 (tests-passed), are vulnerable to cross-site Scripting. A maliciously crafted URL can be included in a post to carry out cross-site scripting attacks on sites with disabled or overly permissive CSP (Content Security Policy). Discourse's default CSP prevents this vulnerability. This vulnerability is patched in versions 2.8.13 (stable), 3.0.0.beta16 (beta) and 3.0. ... Discourse is an open source platform for community discussion. Versions prior to 2.8.13 (stable), 3.0.0.beta16 (beta) and 3.0.0beta16 (tests-passed), are vulnerable to cross-site Scripting. A maliciously crafted URL can be included in a post to carry out cross-site scripting attacks on sites with disabled or overly permissive CSP (Content Security Policy). Discourse's default CSP prevents this vulnerability. This vulnerability is patched in versions 2.8.13 (stable), 3.0.0.beta16 (beta) and 3.0.0beta16 (tests-passed). As a workaround, enable and/or restore your site's CSP to the default one provided with Discourse.

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Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 3.0.0.beta16 on the `beta` and `tests-passed` branches, tag descriptions, which can be updated by moderators, can be used for cross-site scripting attacks. This vulnerability can lead to a full XSS on sites which have modified or disabled Discourse’s default Content Security Policy. Versions 2.8.14 and 3.0.0.beta16 contain a patch.

Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 3.0.0.beta16 on the `beta` and `tests-passed` branches, pending post titles can be used for cross-site scripting attacks. Pending posts can be created by unprivileged users when a category has the "require moderator approval of all new topics" setting set. This vulnerability can lead to a full XSS on sites which have modified or disabled Discourse’s default Content Security Policy. A pat ... Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 3.0.0.beta16 on the `beta` and `tests-passed` branches, pending post titles can be used for cross-site scripting attacks. Pending posts can be created by unprivileged users when a category has the "require moderator approval of all new topics" setting set. This vulnerability can lead to a full XSS on sites which have modified or disabled Discourse’s default Content Security Policy. A patch is available in versions 2.8.14 and 3.0.0.beta16.

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Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 3.0.0.beta16 on the `beta` and `tests-passed` branches, the number of times a user posted in an arbitrary topic is exposed to unauthorized users through the `/u/username.json` endpoint. The issue is patched in version 2.8.14 and 3.0.0.beta16. There is no known workaround.

Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 3.0.0.beta16 on the `beta` and `tests-passed` branches, when a user requests for a password reset link email, then changes their primary email, the old reset email is still valid. When the old reset email is used to reset the password, the Discourse account's primary email would be re-linked to the old email. If the old email address is compromised or has transferred ownership, this lead ... Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 3.0.0.beta16 on the `beta` and `tests-passed` branches, when a user requests for a password reset link email, then changes their primary email, the old reset email is still valid. When the old reset email is used to reset the password, the Discourse account's primary email would be re-linked to the old email. If the old email address is compromised or has transferred ownership, this leads to an account takeover. This is however mitigated by the SiteSetting `email_token_valid_hours` which is currently 48 hours. Users should upgrade to versions 2.8.14 or 3.0.0.beta15 to receive a patch. As a workaround, lower `email_token_valid_hours ` as needed.

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Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 2.9.0.beta15 on the `beta` and `tests-passed` branches, recipients of a group SMTP email could see the email addresses of all other users inside the group SMTP topic. Most of the time this is not an issue as they are likely already familiar with one another's email addresses. This issue is patched in versions 2.8.14 and 2.9.0.beta15. The fix is that someone sending emails out via group S ... Discourse is an option source discussion platform. Prior to version 2.8.14 on the `stable` branch and version 2.9.0.beta15 on the `beta` and `tests-passed` branches, recipients of a group SMTP email could see the email addresses of all other users inside the group SMTP topic. Most of the time this is not an issue as they are likely already familiar with one another's email addresses. This issue is patched in versions 2.8.14 and 2.9.0.beta15. The fix is that someone sending emails out via group SMTP to non-staged users masks those emails with blind carbon copy (BCC). Staged users are ones that have likely only interacted with the group via email, and will likely include other people who were CC'd on the original email to the group. As a workaround, disable group SMTP for any groups that have it enabled.

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Discourse is an open-source discussion platform. In version 2.8.13 and prior on the `stable` branch and version 2.9.0.beta14 and prior on the `beta` and `tests-passed` branches, any authenticated user can create an unlisted topic. These topics, which are not readily available to other users, can take up unnecessary site resources. A patch for this issue is available in the `main` branch of Discourse. There are no known workarounds available.

Discourse is an open-source discussion platform. Prior to version 2.8.13 of the `stable` branch and version 2.9.0.beta14 of the `beta` and `tests-passed` branches, unauthorized users may learn of the existence of hidden tags and that they have been applied to topics that they have access to. This issue is patched in version 2.8.13 of the `stable` branch and version 2.9.0.beta14 of the `beta` and `tests-passed` branches. As a workaround, use the `disable_email` site setting to disable all emails ... Discourse is an open-source discussion platform. Prior to version 2.8.13 of the `stable` branch and version 2.9.0.beta14 of the `beta` and `tests-passed` branches, unauthorized users may learn of the existence of hidden tags and that they have been applied to topics that they have access to. This issue is patched in version 2.8.13 of the `stable` branch and version 2.9.0.beta14 of the `beta` and `tests-passed` branches. As a workaround, use the `disable_email` site setting to disable all emails to non-staff users.

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Discourse is an open-source messaging platform. In versions 2.8.10 and prior on the `stable` branch and versions 2.9.0.beta11 and prior on the `beta` and `tests-passed` branches, users composing malicious messages and navigating to drafts page could self-XSS. This vulnerability can lead to a full XSS on sites which have modified or disabled Discourse’s default Content Security Policy. This issue is patched in the latest stable, beta and tests-passed versions of Discourse.

Discourse is an open-source discussion platform. In stable versions prior to 2.8.12 and beta or tests-passed versions prior to 2.9.0.beta.13, under certain conditions, a user can see notifications for topics they no longer have access to. If there is sensitive information in the topic title, it will therefore have been exposed. This issue is patched in stable version 2.8.12, beta version 2.9.0.beta13, and tests-passed version 2.9.0.beta13. There are no workarounds available.

Discourse is an open-source discussion platform. Prior to version 2.9.0.beta13, users can post chat messages of an unlimited length, which can cause a denial of service for other users when posting huge amounts of text. Users should upgrade to version 2.9.0.beta13, where a limit has been introduced. No known workarounds are available.

Discourse is the an open source discussion platform. In some rare cases users redeeming an invitation can be added as a participant to several private message topics that they should not be added to. They are not notified of this, it happens transparently in the background. This issue has been resolved in commit `a414520742` and will be included in future releases. Users are advised to upgrade. Users are also advised to set `SiteSetting.max_invites_per_day` to 0 until the patch is installed.

Discourse is a platform for community discussion. Under certain conditions, a user badge may have been awarded based on a user's activity in a topic with restricted access. Before this vulnerability was disclosed, the topic title of the topic associated with the user badge may be viewed by any user. If there are sensitive information in the topic title, it will therefore have been exposed. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. There are currentl ... Discourse is a platform for community discussion. Under certain conditions, a user badge may have been awarded based on a user's activity in a topic with restricted access. Before this vulnerability was disclosed, the topic title of the topic associated with the user badge may be viewed by any user. If there are sensitive information in the topic title, it will therefore have been exposed. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. There are currently no known workarounds available.

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Discourse is a platform for community discussion. Users who receive an invitation link that is not scoped to a single email address can enter any non-admin user's email and gain access to their account when accepting the invitation. All users should upgrade to the latest version. A workaround is temporarily disabling invitations with `SiteSetting.max_invites_per_day = 0` or scope them to individual email addresses.

Discourse is a platform for community discussion. A malicious admin could use this vulnerability to perform port enumeration on the local host or other hosts on the internal network, as well as against hosts on the Internet. Latest `stable`, `beta`, and `test-passed` versions are now patched. As a workaround, self-hosters can use `DISCOURSE_BLOCKED_IP_BLOCKS` env var (which overrides `blocked_ip_blocks` setting) to stop webhooks from accessing private IPs.

Discourse is an open source discussion platform. Starting with version 2.9.0.beta5 and prior to version 2.9.0.beta10, an incomplete quote can generate a JavaScript error which will crash the current page in the browser in some cases. Version 2.9.0.beta10 added a fix and tests to ensure incomplete quotes won't break the app. As a workaround, the quote can be fixed via the rails console.

Discourse is an open source discussion platform. In versions prior to 2.8.9 on the `stable` branch and prior to 2.9.0.beta10 on the `beta` and `tests-passed` branches, a malicious actor can add large payloads of text into the Location and Website fields of a user profile, which causes issues for other users when loading that profile. A fix to limit the length of user input for these fields is included in version 2.8.9 on the `stable` branch and version 2.9.0.beta10 on the `beta` and `tests-passe ... Discourse is an open source discussion platform. In versions prior to 2.8.9 on the `stable` branch and prior to 2.9.0.beta10 on the `beta` and `tests-passed` branches, a malicious actor can add large payloads of text into the Location and Website fields of a user profile, which causes issues for other users when loading that profile. A fix to limit the length of user input for these fields is included in version 2.8.9 on the `stable` branch and version 2.9.0.beta10 on the `beta` and `tests-passed` branches. There are no known workarounds.

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Discourse through 2.8.7 allows admins to send invitations to arbitrary email addresses at an unlimited rate.

Discourse is an open source discussion platform. In versions prior to 2.8.9 on the `stable` branch and prior to 2.9.0.beta10 on the `beta` and `tests-passed` branches, a moderator can create new and edit existing themes by using the API when they should not be able to do so. The problem is patched in version 2.8.9 on the `stable` branch and version 2.9.0.beta10 on the `beta` and `tests-passed` branches. There are no known workarounds.

Discourse is an open source discussion platform. In versions prior to 2.8.9 on the `stable` branch and prior to 2.9.0.beta10 on the `beta` and `tests-passed` branches, admins can upload a maliciously crafted Zip or Gzip Tar archive to write files at arbitrary locations and trigger remote code execution. The problem is patched in version 2.8.9 on the `stable` branch and version 2.9.0.beta10 on the `beta` and `tests-passed` branches. There are no known workarounds.

Discourse is the an open source discussion platform. In affected versions an email activation route can be abused to send mass spam emails. A fix has been included in the latest stable, beta and tests-passed versions of Discourse which rate limits emails. Users are advised to upgrade. Users unable to upgrade should manually rate limit email.

Discourse is the an open source discussion platform. In affected versions a maliciously crafted request for static assets could cause error responses to be cached by Discourse's default NGINX proxy configuration. A corrected NGINX configuration is included 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 discussion platform. Under certain conditions, a logged in user can redeem an invite with an email that either doesn't match the invite's email or does not adhere to the email domain restriction of an invite link. The impact of this flaw is aggravated when the invite has been configured to add the user that accepts the invite into restricted groups. Once a user has been incorrectly added to a restricted group, the user may then be able to view content which that are r ... Discourse is an open source discussion platform. Under certain conditions, a logged in user can redeem an invite with an email that either doesn't match the invite's email or does not adhere to the email domain restriction of an invite link. The impact of this flaw is aggravated when the invite has been configured to add the user that accepts the invite into restricted groups. Once a user has been incorrectly added to a restricted group, the user may then be able to view content which that are restricted to the respective group. Users are advised to upgrade to the current stable releases. There are no known workarounds to this issue.

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Discourse is an open-source discussion platform. Prior to version 2.8.4 in the `stable` branch and version `2.9.0.beta5` in the `beta` and `tests-passed` branches, banner topic data is exposed on login-required sites. This issue is patched in version 2.8.4 in the `stable` branch and version `2.9.0.beta5` in the `beta` and `tests-passed` branches of Discourse. As a workaround, one may disable banners.

Discourse is an open source platform for community discussion. Prior to version 2.8.4 on the `stable` branch and 2.9.0beta5 on the `beta` and `tests-passed` branches, inviting users on sites that use single sign-on could bypass the `must_approve_users` check and invites by staff are always approved automatically. The issue is patched in Discourse version 2.8.4 on the `stable` branch and version `2.9.0.beta5` on the `beta` and `tests-passed` branches. As a workaround, disable invites or increase ... Discourse is an open source platform for community discussion. Prior to version 2.8.4 on the `stable` branch and 2.9.0beta5 on the `beta` and `tests-passed` branches, inviting users on sites that use single sign-on could bypass the `must_approve_users` check and invites by staff are always approved automatically. The issue is patched in Discourse version 2.8.4 on the `stable` branch and version `2.9.0.beta5` on the `beta` and `tests-passed` branches. As a workaround, disable invites or increase `min_trust_level_to_allow_invite` to reduce the attack surface to more trusted users.

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Discourse is an open source platform for community discussion. A category's group permissions settings can be viewed by anyone that has access to the category. As a result, a normal user is able to see whether a group has read/write permissions in the category even though the information should only be available to the users that can manage a category. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. There are no workarounds for this problem.

Discourse is an open source platform for community discussion. In affected versions an attacker can poison the cache for anonymous (i.e. not logged in) users, such that the users are shown the crawler view of the site instead of the HTML page. This can lead to a partial denial-of-service. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. There are no known workarounds for this issue.

Discourse is an open source platform for community discussion. In stable versions prior to 2.8.3 and beta versions prior 2.9.0.beta4 erroneously expose groups. When a group with restricted visibility has been used to set the permissions of a category, the name of the group is leaked to any user that is able to see the category. To workaround the problem, a site administrator can remove groups with restricted visibility from any category's permissions setting.