github.com/mattermost/mattermost-server

An issue was discovered in Mattermost Server before 4.0.0, 3.10.2, and 3.9.2. It allows XSS via an uploaded file.

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 4.0.0, 3.10.2, and 3.9.2, when Single Sign-On OAuth2 is used. An attacker could claim somebody else's account.

An issue was discovered in Mattermost Server before 4.0.0, 3.10.2, and 3.9.2. XSS could occur via a channel header.

An issue was discovered in Mattermost Server before 4.0.0, 3.10.2, and 3.9.2. A password-reset request was sometime sent to an attacker-provided e-mail address.

An issue was discovered in Mattermost Server before 3.9.0 when SAML is used. Encryption and signature verification are not mandatory.

An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. The X.509 certificate validation can be skipped for a TLS-based e-mail server.

An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. It allows an attacker to specify a full pathname of a log file.

An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. After a restart of a server, an attacker might suddenly gain API Endpoint access.

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 3.8.2, 3.7.5, and 3.6.7. Weak hashing was used for e-mail invitations, OAuth, and e-mail verification tokens.

An issue was discovered in Mattermost Server before 3.7.3 and 3.6.5. A System Administrator can place a SAML certificate at an arbitrary pathname.

An issue was discovered in Mattermost Server before 5.1. It allows attackers to cause a denial of service via the invite_people slash command.

An issue was discovered in Mattermost Server before 5.20.0. Non-members can receive broadcasted team details via the update_team WebSocket event, aka MMSA-2020-0012.

Mattermost 5.38 and earlier fails to sufficiently sanitize clipboard contents, which allows a user-assisted attacker to inject arbitrary web script in product deployments that explicitly disable the default CSP.

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 confi…

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.

Mattermost version 6.4.x and earlier fails to properly check the plugin version when a plugin is installed from the Marketplace, which allows an authenticated and an authorized user to install and exploit an old plugin version from the Mar…

Mattermost 6.4.x and earlier fails to properly invalidate pending email invitations when the action is performed from the system console, which allows accidentally invited users to join the workspace and access information from the public …

Uncontrolled resource consumption in Mattermost version 6.6.0 and earlier allows an authenticated attacker to crash the server via a crafted SVG attachment on a post.

Unrestricted information disclosure of all users in Mattermost version 6.7.0 and earlier allows team members to access some sensitive information by directly accessing the APIs.

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 allows an authenticated user to crash the server via multiple requests to one of the API endpoints which could fetch a large amount of data. 

When processing an email invite to a private channel on a team, Mattermost fails to validate the inviter's permission to that channel, allowing an attacker to invite themselves to a private channel.

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 con…

vulnerable: 7.8.0

Boards in Mattermost allows an attacker to upload a malicious SVG image file as an attachment to a card and share it using a direct link to the file.

vulnerable: 7.8.0

Mattermost allows an attacker to request a preview of an existing message when creating a new message via the createPost API call, disclosing the contents of the linked message.

Mattermost fails to properly verify the permissions needed for viewing archived public channels,  allowing a member of one team to get details about the archived public channels of another team via the GET /api/v4/teams/<team-id>/channe…

Mattermost fails to scope the WebSocket response around notified users to a each user separately resulting in the WebSocket broadcasting the information about who was notified about a post to everyone else in the channel.

Mattermost fails to update the permissions of the current session for a user who was just demoted to guest, allowing freshly demoted guests to change group names.

Mattermost fails to properly sanitize the user object when updating the username, resulting in the password hash being included in the response body. 

Mattermost version 8.1.6 and earlier fails to sanitize channel mention data in posts, which allows an attacker to inject markup in the web client.

Mattermost versions 9.11.X <= 9.11.1, 9.5.x <= 9.5.9 icorrectly issues two sessions when using desktop SSO - one in the browser and one in desktop with incorrect settings.

Mattermost versions 9.5.x <= 9.5.9 fail to properly filter the channel data when ElasticSearch is enabled which allows a user to get private channel names by using cmd+K/ctrl+K.

Mattermost fails to check if a custom emoji reaction exists when sending it to a post and to limit the amount of custom emojis allowed to be added in a post, allowing an attacker sending a huge amount of non-existent custom emojis in a pos…

Mattermost fails to check if compliance export is enabled when fetching posts of public channels allowing a user that is not a member of the public channel to fetch the posts, which will not be audited in the compliance export. 

Mattermost fails to check the "invite_guest" permission when inviting guests of other teams to a team, allowing a member with permissions to add other members but not to add guests to add a guest to a team as long as the guest was alread…

Mattermost versions 8.1.x before 8.1.9, 9.2.x before 9.2.5, and 9.3.0 fail to sanitize the metadata on posts containing permalinks under specific conditions, which allows an authenticated attacker to access the contents of individual posts…

A race condition in Mattermost versions 8.1.x before 8.1.9, and 9.4.x before 9.4.2 allows an authenticated attacker to gain unauthorized access to individual posts' contents via carefully timed post creation while another user deletes post…

Mattermost version 8.1.x before 8.1.9 fails to sanitize data associated with permalinks when a plugin updates an ephemeral post, allowing an authenticated attacker who can control the ephemeral post update to access individual posts' conte…

Mattermost versions 8.1.x before 8.1.9, 9.2.x before 9.2.5, 9.3.0, and 9.4.x before 9.4.2 fail to limit the number of role names requested from the API, allowing an authenticated attacker to cause the server to run out of memory and crash …

Improper Access Control in Mattermost Server versions 8.1.x before 8.1.11 allows an attacker that is in a channel with an active call to keep participating in the call even if they are removed from the channel

Mattermost versions 8.1.x <= 8.1.10, 9.6.x <= 9.6.0, 9.5.x <= 9.5.2 and 8.1.x <= 8.1.11 fail to limit the size of a request path that includes user inputs which allows an attacker to cause excessive resource consumption, possibly leading…

Mattermost fails to properly restrict the access of files attached to posts in an archived channel, resulting in members being able to access files of archived channels even if the “Allow users to view archived channels” option is disa…

Mattermost fails to properly authorize the requests fetching team associated AD/LDAP groups, allowing a user to fetch details of AD/LDAP groups of a team that they are not a member of. 

Mattermost versions 8.1.x before 8.1.11, 9.3.x before 9.3.3, 9.4.x before 9.4.4, and 9.5.x before 9.5.2 fail to authenticate the source of certain types of post actions, allowing an authenticated attacker to create posts as other users via…

Mattermost fails to check the required permissions in the POST /api/v4/channels/stats/member_count API resulting in channel member counts being leaked to a user without permissions.

Mattermost fails to properly validate the length of the emoji value in the custom user status, allowing an attacker to send multiple times a very long string as an emoji value causing high resource consumption and possibly crashing the se…

Resource Exhaustion in Mattermost Server versions 8.1.x before 8.1.10 fails to limit the size of the payload that can be read and parsed allowing an attacker to send a very large email payload and crash the server.

Mattermost Server versions 9.5.x before 9.5.2, 9.4.x before 9.4.4, 9.3.x before 9.3.3, 8.1.x before 8.1.11 don't limit the number of user preferences which allows an attacker to send a large number of user preferences potentially causing d…