Mattermost iOS app fails to properly validate the server certificate while initializing the TLS connection allowing a network attacker to intercept the WebSockets connection.

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 use innerText /textContentwhen setting the channel ...

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 unescape Markdown strings in a memory-efficient wa ...

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.

Mattermost fails to normalize UTF confusable characters when determini ...

Mattermost fails to sanitize code permalinks, allowing an attacker to preview code from private repositories by posting a specially crafted permalink on a channel.

Mattermost fails to sanitize code permalinks, allowing an attacker to ...

Mattermost fails to validate links on external websites when constructing a preview for a linked website, allowing an attacker to cause a denial-of-service by a linking to a specially crafted webpage in a message.

Mattermost fails to validate links on external websites when construct ...

Mattermost fails to sanitize ephemeral error messages, allowing an attacker to obtain arbitrary message contents by a specially crafted /groupmsg command.

Mattermost fails to sanitize ephemeral error messages, allowing an att ...

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.

When creating a playbook run via the /dialog API, Mattermost fails to ...

Mattermost fails to check if an admin user account active after an oauth2 flow is started, allowing an attacker with admin privileges to retain persistent access to Mattermost by obtaining an oauth2 access token while the attacker's account is deactivated.

Mattermost fails to check if an admin user account active after an oau ...

Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.

Mattermost fails to check channel membership when accessing message th ...

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.