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

Mattermost fails to invalidate existing authorization codes when deauthorizing an OAuth2 app, allowing an attacker possessing an authorization code to generate an access token.

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.

A missing permissions check in Mattermost Playbooks in Mattermost allows an attacker to modify a playbook via the /plugins/playbooks/api/v0/playbooks/[playbookID] API.

An issue was discovered in Mattermost Server before 5.8.0. It does not always generate a robots.txt file.

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.

Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to read the content of threads in private channels and direct messages they do not have access to via a crafted request to the post rewrite endpoint.. Mattermost Advisory ID: MMSA-2026-00645

Mattermost versions 9.10.x <= 9.10.2, 9.11.x <= 9.11.1, 9.5.x <= 9.5.9 fail to check that the origin of the message in an integration action matches with the original post metadata which allows an authenticated user to delete an arbitrary post.

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to check the create_post channel permission during post edit operations which allows an authenticated attacker with revoked posting privileges to modify their existing posts via direct API requests to the post update and patch endpoints.. Mattermost Advisory ID: MMSA-2026-00627

Mattermost Plugin Legal Hold versions <=1.1.4 fail to halt request processing after a failed authorization check in ServeHTTP which allows an authenticated attacker to access, create, download, and delete legal hold data via crafted API requests to the plugin's endpoints. Mattermost Advisory ID: MMSA-2026-00621

An issue was discovered in Mattermost Server before 5.2 and 5.1.1. Authorization could be bypassed if the channel name were not the same in the params and the body.

Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to properly check for permissions when processing commands in the Gitlab plugin which allows normal users to uninstall instances or setup webhook connections via the {{gitlab instance {option}}} or the {{/gitlab webhook {option}}} commands. Mattermost Advisory ID: MMSA-2026-00600

Mattermost versions 10.11.x <= 10.11.12 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicious remote server connected using the Conntexted Workspaces feature to change the displayed status of local users via the Connected Workspaces API.. Mattermost Advisory ID: MMSA-2026-00603

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 and Mattermost Plugin Zoom versions <=1.11.0 fail to validate user identity and post ownership in the {{/api/v1/askPMI}} endpoint which allows unauthorized users to start Zoom meetings as any user and overwrite arbitrary posts via direct API calls with manipulated user IDs and post data.. Mattermost Advisory ID: MMSA-2025-00534

Mattermost versions 10.10.x <= 10.10.1 fail to properly sanitize user data during shared channel membership synchronization, which allows malicious or compromised remote clusters to access sensitive user information via unsanitized user objects. This vulnerability affects Mattermost Server instances with shared channels enabled.

Mattermost Confluence Plugin version <1.5.0 fails to check the access of the user to the channel which allows attackers to create channel subscription without proper access to the channel via API call to the create channel subscription endpoint.

Mattermost versions 10.11.x <= 10.11.1, 10.10.x <= 10.10.2, 10.5.x <= 10.5.10 fail to verify a user has permission to join a Mattermost team using the original invite token which allows any attacked to join any team on a Mattermost server regardless of restrictions via manipulating the RelayState

Mattermost versions 10.11.x <= 10.11.1, 10.10.x <= 10.10.2, 10.5.x <= 10.5.10 fail to verify a user has permission to join a Mattermost team using the original invite token which allows any attacked to join any team on a Mattermost server regardless of restrictions via manipulating the OAuth state.

Mattermost Confluence Plugin version <1.5.0 fails to check the access of the user to the Confluence space which allows attackers to create a subscription for a Confluence space the user does not have access to via the create subscription endpoint.

Mattermost Confluence Plugin version <1.5.0 fails to check the access of the user to the channel which allows attackers to create a channel subscription without proper access to the channel via API call to the edit channel subscription endpoint.

Mattermost Confluence Plugin version <1.5.0 fails to enforce authentication of the user to the Mattermost instance which allows unauthenticated attackers to access subscription details without via API call to GET subscription endpoint.

Mattermost Confluence Plugin version <1.5.0 fails to check the access of the user to the Confluence space which allows attackers to edit a subscription for a Confluence space the user does not have access for via edit subscription endpoint.

Mattermost Confluence Plugin version <1.5.0 fails to check the access of the user to the channel which allows attackers to get channel subscription details without proper access to the channel via API call to the Get Channel Subscriptions details endpoint.

Mattermost versions 10.10.x <= 10.10.2, 10.5.x <= 10.5.10, 10.11.x <= 10.11.2 fail to validate email ownership during Slack import process which allows attackers to create verified user accounts with arbitrary email domains via malicious Slack import data to bypass email-based team access restrictions

Mattermost Confluence Plugin version <1.5.0 fails to check the access of the user to the channel which allows attackers to get channel subscription details without proper access to the channel via API call to the GET autocomplete/GetChannelSubscriptions endpoint.

An issue was discovered in Mattermost Server before 5.1. It allows attackers to bypass intended access restrictions (for setting a channel header) via the Channel header slash command API.

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 versions 10.11.x <= 10.11.9 fail to enforce invite permissions when updating team settings, which allows team administrators without proper permissions to bypass restrictions and add users to their team via API requests. Mattermost Advisory ID: MMSA-2025-00561

Mattermost fails to check if the requesting user is a guest before performing different actions to public playbooks, resulting a guest being able to view, join, edit, export and archive public playbooks.

Mattermost fails to properly show information in the UI, allowing a system admin to modify a board state allowing any user with a valid sharing link to join the board with editor access, without the UI showing the updated permissions.

The direct_mail extension through 5.2.3 for TYPO3 has Broken Access Control for newsletter subscriber tables.

Missing Authorization vulnerability in AudioTheme Cue cue allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Cue: from n/a through <= 2.4.4.

Missing Authorization vulnerability in acmemediakits ACME Divi Modules acme-divi-modules allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects ACME Divi Modules: from n/a through <= 1.3.5.

Missing Authorization vulnerability in JS Morisset JSM Show Post Metadata jsm-show-post-meta allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects JSM Show Post Metadata: from n/a through <= 4.6.0.

Missing Authorization vulnerability in Travis Simple Icons simple-icons allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Simple Icons: from n/a through <= 2.8.4.

Missing Authorization vulnerability in Wordapp Team Wordapp wordapp allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Wordapp: from n/a through <= 1.7.0.

Missing Authorization vulnerability in SlicedInvoices Sliced Invoices sliced-invoices allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Sliced Invoices: from n/a through <= 3.10.0.

The direct_mail extension through 5.2.3 for TYPO3 allows Information Disclosure via a newsletter subscriber data Special Query.

Missing Authorization vulnerability in inspry Agency Toolkit agency-toolkit allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Agency Toolkit: from n/a through <= 1.0.24.

The B2BKing plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the 'b2bkingdownloadpricelist' function in versions up to, and including, 4.6.00. This makes it possible for Authenticated attackers with subscriber or customer-level permissions to retrieve the full pricing list of all products on the site.

The Page-list plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 6.2. This is due to the pagelist_unqprfx_ext_shortcode() function (the [pagelist_ext] / [pagelistext] shortcode) accepting attacker-controlled post_status, post_type, and show_meta_key attributes and passing them directly into get_pages() and get_post_meta() with no capability check verifying that the rendering user is permitted to read the matched objects. When the current post has no child pages, the shortcode re-issues the query with child_of => 0, broadening it to every page on the site matching the supplied status/type. This makes it possible for authenticated attackers, with contributor-level access and above, to disclose the titles, body content/excerpts, and arbitrary post meta of unrelated private and draft pages by inserting the shortcode into a contributor-authored draft and previewing it.

Missing Authorization vulnerability in Hossni Mubarak Cool Author Box hm-cool-author-box-widget allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Cool Author Box: from n/a through <= 2.9.9.

The myCred WordPress plugin before 2.4.3.1 does not have authorisation and CSRF checks in its mycred-tools-import-export AJAX action, allowing any authenticated user to call and and retrieve the list of email address present in the blog

A missing permission check in Jenkins Team Foundation Server Plugin 5.157.1 and earlier allows attackers with Overall/Read permission to enumerate credentials ID of credentials stored in Jenkins.

Missing Authorization vulnerability in WPZOOM Recipe Card Blocks for Gutenberg & Elementor recipe-card-blocks-by-wpzoom allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Recipe Card Blocks for Gutenberg & Elementor: from n/a through <= 3.4.3.

The RSVP and Event Management Plugin WordPress plugin before 2.7.8 does not have any authorisation checks when exporting its entries, and has the export function hooked to the init action. As a result, unauthenticated attackers could call it and retrieve PII such as first name, last name and email address of user registered for events

GeoServer is an open source server that allows users to share and edit geospatial data. It is possible to bypass the default REST API security and access the index page. The REST API security handles rest and its subpaths but not rest with an extension (e.g., rest.html). The REST API index can disclose whether certain extensions are installed. This vulnerability is fixed in 2.26.3 and 2.25.6. As a workaround, in ${GEOSERVER_DATA_DIR}/security/config.xml, change the paths for the rest filter to /rest.*,/rest/** and change the paths for the gwc filter to /gwc/rest.*,/gwc/rest/** and restart GeoServer.

Missing Authorization vulnerability in NotFound Pie Register Premium. This issue affects Pie Register Premium: from n/a through 3.8.3.2.