Mattermost

Mattermost fails to handle a null request body in the /add endpoint, allowing a simple member to send a request with null request body to that endpoint and make it crash. After a few repetitions, the plugin is disabled. 

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 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 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 limit the log size of server logs allowing an attacker sending specially crafted requests to different endpoints to potentially overflow the log.

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 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}/mobile_login?redirect_to=

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…

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 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…

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 Mobile fails to limit the maximum number of Markdown elements in a post allowing an attacker to send a post with hundreds of emojis to a channel and freeze the mobile app of users when viewing that particular channel. 

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 properly check the creator of an attached file when adding the file to a draft post, potentially exposing unauthorized file information.

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 check the Show Full Name option at the /api/v4/teams/TEAM_ID/top/team_members endpoint allowing a member to get the full name of another user even if the Show Full Name option was disabled

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 properly validate a gif image file, allowing an attacker to consume a significant amount of server resources, making the server unresponsive for an extended period of time by linking to specially crafted image file.

Mattermost fails to properly validate markdown, allowing an attacker to crash the server via a specially crafted markdown input.

Mattermost Boards fail to properly validate a board link, allowing an attacker to crash a channel by posting a specially crafted boards link.

Mattermost fails to verify channel membership when linking a board to a channel allowing a low-privileged authenticated user to link a Board to a private channel they don't have access to, 

Mattermost fails to unescape Markdown strings in a memory-efficient way, allowing an attacker to cause a Denial of Service by sending a message containing a large number of escaped characters.

Mattermost fails to properly truncate the postgres error log message of a search query failure allowing an attacker to cause the creation of large log files which can result in Denial of Service

When creating a playbook run via the /dialog API, Mattermost fails to validate all parameters, allowing an authenticated attacker to edit an arbitrary channel post.

Mattermost fails to properly check the permissions when executing commands allowing a member with no permissions to post a message in a channel to actually post it by executing channel commands.

Mattermost Apps Framework fails to verify that a secret provided in the incoming webhook request allowing an attacker to modify the contents of the post sent by the Apps.

Mattermost fails to normalize UTF confusable characters when determining if a preview should be generated for a hyperlink, allowing an attacker to trigger link preview on a disallowed domain using a specially crafted link.

When running in a High Availability configuration, Mattermost fails to sanitize some of the user_updated and post_deleted events broadcast to all users, leading to disclosure of sensitive information to some of the users with currently connected Websocket clients.

A missing permissions check in the /plugins/playbooks/api/v0/runs API in Mattermost allows an attacker to list and view playbooks belonging to a team they are not a member of.

A denial-of-service vulnerability in Mattermost allows an authenticated user to crash the server via multiple large autoresponder messages.

A denial-of-service vulnerability in the Mattermost Playbooks plugin allows an authenticated user to crash the server via multiple large requests to one of the Playbooks API endpoints.

The Guest account feature in Mattermost version 6.7.0 and earlier fails to properly restrict the permissions, which allows a guest user to fetch a list of all public channels in the team, in spite of not being part of those channels.

The legacy Slack import feature in Mattermost version 6.7.0 and earlier fails to properly limit the sizes of imported files, which allows an authenticated attacker to crash the server by importing large files via the Slack import REST API.

The image proxy component in Mattermost version 6.4.1 and earlier allocates memory for multiple copies of a proxied image, which allows an authenticated attacker to crash the server via links to very large image files.

One of the API in Mattermost version 6.4.1 and earlier fails to properly protect the permissions, which allows the authenticated members with restricted custom admin role to bypass the restrictions and view the server logs and server config.json file contents.

A stack overflow bug in the document extractor in Mattermost Server in versions up to and including 6.3.2 allows an attacker to crash the server via submitting a maliciously crafted Apple Pages document.

Mattermost 6.3.0 and earlier fails to protect email addresses of the creator of the team via one of the APIs, which allows authenticated team members to access this information resulting in sensitive & private information disclosure.

Mattermost Boards plugin v0.10.0 and earlier fails to protect email addresses of all users via one of the Boards APIs, which allows authenticated and unauthorized users to access this information resulting in sensitive & private information disclosure.

Mattermost 6.2 and earlier fails to sufficiently process a specifically crafted GIF file when it is uploaded while drafting a post, which allows authenticated users to cause resource exhaustion while processing the file, resulting in server-side Denial of Service.

An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. API endpoint access control does not honor an integration permission restriction.

An issue was discovered in Mattermost Server before 4.0.0, 3.10.2, and 3.9.2, when used as an OAuth 2.0 service provider, Session invalidation was mishandled.

An issue was discovered in Mattermost Server before 3.0.0. It does not ensure that a cookie is used over SSL.

An issue was discovered in Mattermost Server before 3.0.0. It allows attackers to obtain sensitive information about team URLs via an API.

An issue was discovered in Mattermost Server before 3.1.0. It allows XSS via theme color-code values.

An issue was discovered in Mattermost Server before 3.2.0. Attackers could read LDAP fields via injection.

An issue was discovered in Mattermost Server before 3.2.0. It allowed crafted posts that could cause a web browser to hang.

An issue was discovered in Mattermost Server before 3.5.1. E-mail address verification can be bypassed.

An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. E-mail notifications can have spoofed links.

An issue was discovered in Mattermost Server before 4.1.0, 4.0.4, and 3.10.3. It allows attackers to discover a team invite ID by requesting a JSON document.