Discourse: >> Discourse >> 2.9.0 Security Vulnerabilities
Discourse is an open-source community platform. A data leak vulnerability affects sites deployed between commits 10df7fdee060d44accdee7679d66d778d1136510 and 82d84af6b0efbd9fa2aeec3e91ce7be1a768511b. On login-required sites, the leak meant that some content on the site's homepage could be visible to unauthenticated users. Only login-required sites that got deployed during this timeframe are affected, roughly between April 30 2025 noon EDT and May 2 2025, noon EDT. Sites on the stable branch are unaffected. Private content on an instance's homepage could be visible to unauthenticated users on login-required sites. Versions of 3.5.0.beta4 after commit 82d84af6b0efbd9fa2aeec3e91ce7be1a768511b are not vulnerable to the issue. No workarounds are available. Sites must upgrade to a non-vulnerable version of Discourse.
CVSS Score
5.8
EPSS Score
0.001
Published
2025-05-05
Discourse is an open-source discussion platform. Prior to versions 3.4.3 on the stable branch and 3.5.0.beta3 on the beta branch, the users limit for a DM can be bypassed, thus giving the ability to potentially create a DM with every user from a site in it. This issue has been patched in stable version 3.4.3 and beta version 3.5.0.beta3.
CVSS Score
4.3
EPSS Score
0.0
Published
2025-04-30
Discourse is an open-source discussion platform. Prior to versions `3.3.4` on the `stable` branch and `3.4.0.beta5` on the `beta` branch, in specific circumstances, users could be added to group direct messages despite disabling direct messaging in their preferences. Versions `3.3.4` and `3.4.0.beta5` contain a patch for the issue. A workaround is available. If a user disables chat in their preferences then they cannot be added to new group chats.
CVSS Score
4.3
EPSS Score
0.001
Published
2025-03-26
Discourse is an open-source discussion platform. Prior to versions `3.3.4` on the `stable` branch and `3.4.0.beta5` on the `beta` branch, someone who is about to reach the limit of users in a group DM may send requests to add new users in parallel. The requests might all go through ignoring the limit due to a race condition. The patch in versions `3.3.4` and `3.4.0.beta5` uses the `lock` step in service to wrap part of the `add_users_to_channel` service inside a distributed lock/mutex in order to avoid the race condition.
CVSS Score
4.3
EPSS Score
0.001
Published
2025-03-26
Discourse is an open source platform for community discussion. In affected versions with some combinations of plugins, and with CSP disabled, activity streams in the user's profile page may be vulnerable to XSS. This has been patched in the latest version of Discourse core. Users are advised to upgrade. Users unable to upgrade should ensure CSP is enabled.
CVSS Score
4.3
EPSS Score
0.001
Published
2025-02-04
Discourse is an open source platform for community discussion. In affected versions the endpoint for generating inline oneboxes for URLs wasn't enforcing limits on the number of URLs that it accepted, allowing a malicious user to inflict denial of service on some parts of the app. This vulnerability is only exploitable by authenticated users. This issue has been patched in the latest stable, beta and tests-passed versions of Discourse. Users are advised to upgrade. Users unable to upgrade should turn off the `enable inline onebox on all domains` site setting and remove all entries from the `allowed inline onebox domains` site setting.
CVSS Score
4.3
EPSS Score
0.003
Published
2025-02-04
Discourse is an open source platform for community discussion. In affected versions users who disable chat in preferences could still be reachable in some cases. This problem has been patched in the latest version of Discourse. Users are advised to upgrade. Users unable to upgrade should disable the chat plugin within site settings.
CVSS Score
4.3
EPSS Score
0.001
Published
2025-02-04
Discourse is an open source platform for community discussion. PM titles and metadata can be read by other users when the "PM tags allowed for groups" option is enabled, the other user is a member of a group added to this option, and the PM has been tagged. This issue has been patched in the latest `stable`, `beta` and `tests-passed` versions of Discourse. Users are advised to upgrade. Users unable to upgrade should remove all groups from the the "PM tags allowed for groups" option.
CVSS Score
2.2
EPSS Score
0.002
Published
2025-02-04
Discourse is an open source platform for community discussion. An attacker can execute arbitrary JavaScript on users' browsers by posting a maliciously crafted onebox url. This issue only affects sites with CSP disabled. This problem has been patched in the latest version of Discourse. Users are advised to upgrade. Users unable to upgrade should enable CSP, disable inline Oneboxes globally, or allow specific domains for Oneboxing.
CVSS Score
6.5
EPSS Score
0.001
Published
2025-02-04
Discourse is an open source platform for community discussion. In affected versions an attacker can trick a target user to make changes to their own username via carefully crafted link using the `activate-account` route. This problem has been patched in the latest version of Discourse. Users are advised to upgrade. There are no known workarounds for this vulnerability.
CVSS Score
3.1
EPSS Score
0.003
Published
2025-02-04