Mattermost webapp fails to validate route parameters in/<TEAMNAME>/channels/<CHANNELNAME> allowing an attacker to perform a client-side path traversal.
Mattermost fails to validate if a relative path is passed in /plugins/playbooks/api/v0/telemetry/run/<telemrunid> as a telemetry run ID, allowing an attacker to use a path traversal payload that points to a different endpoint leading to a CSRF attack.
Mattermost fails to restrict which parameters' values it takes from the request during signup allowing an attacker to register users as inactive, thus blocking them from later accessing Mattermost without the system admin activating their accounts.
Mattermost fails to enforce a limit for the size of the cache entry for OpenGraph data allowing an attacker to send a specially crafted request to the /api/v4/opengraph filling the cache and turning the server unavailable.
Mattermost fails to properly limit the characters allowed in different fields of a block in Mattermost Boards allowing a attacker to consume excessive resources, possibly leading to Denial of Service, by patching the field of a block using a specially crafted string.
Mattermost fails to limit the amount of data extracted from compressed archives during board import in Mattermost Boards allowing an attacker to consume excessive resources, possibly leading to Denial of Service, by importing a board using a specially crafted zip (zip bomb).
Mattermost fails to to check the length when setting the title in a run checklist in Playbooks, allowing an attacker to send a specially crafted request and crash the Playbooks plugin
Mattermost fails to validate the type of the "reminder" body request parameter allowing an attacker to crash the Playbook Plugin when updating the status dialog.
Mattermost fails to properly validate the permissions when soft deleting a team allowing a team member to soft delete other teams that they are not part of
Mattermost fails to enforce character limits in all possible notification props allowing an attacker to send a really long value for a notificationprop resulting in the server consuming an abnormal quantity of computing resources and possibly becoming temporarily unavailable for its users.
Mattermost fails to deduplicate input IDs allowing a simple user to cause the application to consume excessive resources and possibly crash by sending a specially crafted request to /api/v4/users/ids with multiple identical IDs.
Mattermost fails to perform authorization checks in the /plugins/playbooks/api/v0/runs/add-to-timeline-dialog endpoint of the Playbooks plugin allowing an attacker to get limited information about a post if they know the post ID
Mattermost fails to properly check a redirect URL parameter allowing for an open redirect was possible when the user clicked "Back to Mattermost" after providing a invalid custom url scheme in /oauth/{service}/mobilelogin?redirectto=
Mattermost fails to use innerText / textContent when setting the channel name in the webapp during autocomplete, allowing an attacker to inject HTML to a victim's page by create a channel name that is valid HTML. No XSS is possible though.
Mattermost fails to properly check the creator of an attached file when adding the file to a draft post, potentially exposing unauthorized file information.
Mattermost fails to properly sanitize the request to /api/v4/redirectlocation allowing an attacker, sending a specially crafted request to /api/v4/redirectlocation, to fill up the memory due to caching large items.
Mattermost fails to limit the log size of server logs allowing an attacker sending specially crafted requests to different endpoints to potentially overflow the log.
Mattermost is grouping calls in the /metrics endpoint by id and reports that id in the response. Since this id is the channelID, the public /metrics endpoint is revealing channelIDs.
Mattermost fails to properly check permissions when retrieving a post allowing for a System Role with the permission to manage channels to read the posts of a DM conversation.
Mattermost fails to properly sanitize the user object when updating the username, resulting in the password hash being included in the response body.
Mattermost fails to properly validate permissions when demoting and deactivating a user allowing for a system/user manager to demote / deactivate another manager
Mattermost fails to check the Show Full Name option at the /api/v4/teams/TEAMID/top/teammembers endpoint allowing a member to get the full name of another user even if the Show Full Name option was disabled
Mattermost fails to properly validate requests to the Calls plugin, allowing an attacker sending a request without a User Agent header to cause a panic and crash the Calls plugin
Mattermost fails to check if hardened mode is enabled when overriding the username and/or the icon when posting a post. If settings allowed integrations to override the username and profile picture when posting, a member could also override the username and icon when making a post even if the Hardened Mode setting was enabled
Mattermost fails to perform proper authorization in the /plugins/focalboard/api/v2/users endpoint allowing an attacker who is a guest user and knows the ID of another user to get their information (e.g. name, surname, nickname) via Mattermost Boards.
Mattermost fails to properly validate the "Show Full Name" option in a few endpoints in Mattermost Boards, allowing a member to get the full name of another user even if the Show Full Name option was disabled.
Mattermost fails to check whether the “Allow users to view archived channels” setting is enabled during permalink previews display, allowing members to view permalink previews of archived channels even if the “Allow users to view archived channels” setting is disabled.
Mattermost fails to check whether a user is a guest when updating the tasks of a private playbook run allowing a guest to update the tasks of a private playbook run if they know the run ID.
Mattermost fails to properly verify the permissions when managing/updating a bot allowing a User Manager role with user edit permissions to manage/update bots.