207 results · Feed
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Medium 5.5
Malicious remote can create/update/delete arbitrary posts in arbitrary channels
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to properly validate synced posts, when shared channels are enabled, which allows a malicious remote to create/update/delete arbitrary posts in arbitrary channels
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Medium 4.3
Remote username set to an arbitrary string by remote user
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary st…
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Low 3.8
Malicious remote can create arbitrary channels
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6 fail to properly restrict channel creation which allows a malicious remote to create arbitrary channels, when shared channels were enabled.
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Medium 6.8
Permanently local data deletion by malicious remote
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to properly safeguard an error handling which allows a malicious remote to permanently delete local data by abusing dangerous error handling, when share channels were enab…
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High 8.7
Malicious remote can invite itself to an arbitrary local channel
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to disallow unsolicited invites to expose access to local channels, when shared channels are enabled, which allows a malicious remote to send an invite with the ID of a…
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High 8.7
Malicious remote can add users to arbitrary teams and channels
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to properly validate that the channel that comes from the sync message is a shared channel, when shared channels are enabled, which allows a malicious remote to add use…
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High 7.4
Existing local user overwritten by malicious remote
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow the modification of local users when syncing users in shared channels. which allows a malicious remote to overwrite an existing local user.
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Low 2.7
Malicious remote can create arbitrary reactions on arbitrary posts
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6 fail to properly validate synced reactions, when shared channels are enabled, which allows a malicious remote to create arbitrary reactions on arbitrary posts
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Medium 6.5
Mattermost fails to authenticate the source of certain types of post actions
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 a crafted post acti…
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Medium 4.7
Invite ID available to team admins even without the "Add Members" permission
Improper Access Control in 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 lacked proper access control in the `/api/v4/users/me/teams` endpoint allowing a team admin to get the invite ID of their tea…
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Medium 4.3
DoS via a large number of User Preferences
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 denial of service.
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Low 3.1
Users maintain access to active call after being removed from a channel
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
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Low 3.1
Resource Exhaustion via the Invitation Feature
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.
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Medium 4.3
Mattermost fails to limit the number of role names
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 by issuing an unusua…
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Low 3.1
Mattermost incorrectly allows access individual posts
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' contents in channels they…
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Low 2.6
Mattermost race condition
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 posts.
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Medium 4.3
Mattermost allows attackers access to posts in channels they are not a member of
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 in channels they ar…
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Medium 4.3
Existing server guests invited to the team by members without "invite_guest" permission
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 already a guest in another t…
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Medium 4.3
Excessive resource consumption when sending long emoji names in user custom status
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 server.
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Medium 4.3
Public channel post content accessible without membership when compliance export is enabled
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.
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Low 3.1
Files of archived channels accessible with the “Allow users to view archived channels” option disabled
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 disabled.
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Medium 4.3
Team associated AD/LDAP Groups Leaked due to missing authorization
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.
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Medium 4.3
Denial of service in mattermost mobile apps and server via emoji reactions
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 post to crash the mobil…
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Low 3.1
Incorrect Authorization leads to Channel Member Count Leak
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.
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Medium 4.3
Details of archived public channels are leaked to members of another team
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>/channels/deleted endpoint.
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Low 3.7
Lack of restriction to manage group names for freshly demoted guests
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.
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Medium 4.3
Keywords that trigger mentions are leaked to other users
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.
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Low 3.7
Mattermost Cross-site Scripting vulnerability
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.
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Medium 5.3
Public endpoint /metrics of Calls plugin reveals channel IDs
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.
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High 7.1
Client side path traversal due to lack of route parameters validation
Mattermost webapp fails to validate route parameters in/<TEAM_NAME>/channels/<CHANNEL_NAME> allowing an attacker to perform a client-side path traversal.
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Medium 4.3
Open redirect in /oauth/<service>/mobile_login?redirect_to=
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=
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Medium 4.3
Insecure Direct Object Reference in /plugins/focalboard/ api/v2/users of Mattermost Boards
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.
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Medium 4.3
Permalink previews displayed for posts in archived channels even if users are disallowed to view archived channels
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 …
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Medium 4.3
Log Flooding due to specially crafted requests in different endpoints
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.
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Low 3.1
HTML injection via channel autocomplete
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.
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Medium 4.3
Denial of Service via specially crafted block fields in Mattermost Boards
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…
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Medium 4.3
Denial of Service via Board Import Zip Bomb
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…
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Medium 4.3
Users full name disclosure through Mattermost Boards with Show Full Name Option disabled
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.
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Medium 4.3
Username and Icon override can be used by members when Hardened Mode is enabled
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 i…
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Medium 5.3
Denial of Service via Link Preview in /api/v4/redirect_location
Mattermost fails to properly sanitize the request to /api/v4/redirect_location allowing an attacker, sending a specially crafted request to /api/v4/redirect_location, to fill up the memory due to caching large items.