Vendor
Mattermost
512 known vulnerabilities.
Products
42 results · Clear filters · Feed
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High 8.0
Path traversal in Mattermost Agents plugin mention reminder allows plugin replacement via crafted post
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10 fail to validate the target post ID in the Agents plugin's mention reminder component, which allows an authenticated user who can post in a channel visible to a system administrator to …
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High 7.1
Mattermost SAML RelayState forgery allows unauthorized team membership
Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to verify the integrity of the SAML RelayState POST parameter which allows an authenticated SAML user to join any team, including invite-only teams, via forging …
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High 7.1
Playbooks run owner channel membership permission bypass
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate channel member-management permission during playbook run creation, allowing an authenticated channel member to add an arbitrary user to a restricted…
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High 8.3
Insufficient server-side validation of board member role fields permits privilege escalation
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to validate BoardMember.Scheme* fields server-side on insert and archive-import paths which allows a board editor or non-guest team member to grant board admin to arbitrary users…
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High 7.6
CVE-2026-6961: Path traversal via unsanitized FileInfo.Name in Mattermost federation sync
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server…
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High 8.8
Mattermost group syncable endpoints allow privilege escalation via scheme_admin
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints, which allows a user with …
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High 8.0
Path traversal in Mattermost Legal Hold plugin via unsanitized file name from federated peer allows arbitrary file write.
Mattermost Plugins versions <=1.1.5 fail to sanitize filenames received from federated peers before using them to construct export destination paths, which allows an administrator of a remote federated Mattermost server to write files to arbitrary locations w…
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High 7.5
Unauthenticated WebSocket binary frame causes denial of service in Mattermost Server
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to properly validate msgpack-encoded WebSocket frames before memory allocation which allows an unauthenticated remote attacker to crash the server process and c…
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High 8.0
Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to check integration URL for path traversal which allows an malicious authenticated user to call an arbitrary API via system admin Mattermost auth token using v…
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High 8.7
Sensitive credentials exposed in plaintext in Mattermost support packets
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to sanitize sensitive configuration fields before including them in support packet generation, which allows a Mattermost System Admin or any party with access to a support packet…
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High 7.6
Mattermost Calls plugin exposes TURN server credentials in plaintext in support packets
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to sanitize sensitive configuration fields in the Mattermost Calls plugin which allows an attacker with access to a support packet to obtain TURN server credentials via the plain…
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High 8.3
Authorization Bypass in Mattermost Legal Hold Plugin Due to Missing Return After Permission Check
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…
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High 8.1
Focalboard Second-Order SQL Injection in category reorder endpoint allows data exfiltration (unsupported product, no fix)
** UNSUPPORTED WHEN ASSIGNED ** Focalboard version 8.0 fails to sanitize category IDs before incorporating them into dynamic SQL statements when reordering categories. An attacker can inject a malicious SQL payload into the category id field, which is stored …
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High 8.0
Terminal Escape Injection in mmctl Report Posts Command
Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to sanitize user-controlled post content in the mmctl commands terminal output which allows attackers to manipulate administrator terminals via crafted messages…
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High 7.5
DoS attack via login attempts with multi-megabyte passwords
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly handle very long passwords, which allows an attacker to overload the server CPU and memory via executing login attempts with multi-megabyte passwords. Mattermost Advi…
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High 7.6
MS Teams plugin sensitive config values not properly masked in support packets
Mattermost Plugins versions <=2.0.3.0 fail to properly mask sensitive configuration values which allows an attacker with access to support packets to obtain original plugin settings via exported configuration data. Mattermost Advisory ID: MMSA-2026-00606
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High 7.6
Arbitrary application execution via unvalidated server-controlled URLs in Help menu
Mattermost Desktop App versions <=6.0 6.2.0 5.2.13.0 fail to validate help links which allows a malicious Mattermost server to execute arbitrary executables on a user’s system via the user clicking on certain items in the Help menu Mattermost Advisory ID: MMS…
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High 7.7
Cross-Site Scripting (XSS) via Unescaped Display Names in Mattermost Confluence Plugin OAuth2 Flow
Mattermost Confluence plugin version <1.7.0 fails to properly escape user-controlled display names in HTML template rendering which allows authenticated Confluence users with malicious display names to execute arbitrary JavaScript in victim browsers via sendi…
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High 7.2
Mattermost Jira plugin user spoofing enables Jira request forgery.
Mattermost versions 11.1.x <= 11.1.0, 11.0.x <= 11.0.5, 10.12.x <= 10.12.3, 10.11.x <= 10.11.7 with the Jira plugin enabled and Mattermost Jira plugin versions <=4.4.0 fail to enforce authentication and issue-key path restrictions in the Jira plugin, which al…
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High 8.1
Arbitrary Mattermost Team can be joined by manipulating the OAuth state
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 restri…
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High 8.1
Arbitrary Mattermost Team can be joined by manipulating the SAML 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 restri…
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High 8.0
Admin RCE via prepackaged plugins by way of misconfigured imports directory
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to validate import directory path configuration which allows admin users to execute arbitrary code via malicious plugin upload to prepackaged …
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High 7.6
One-Click Mattermost Account Takeover via Poisoned RelayState SAML Parameter
Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4 fail to validate the redirect_to parameter, allowing an attacker to craft a malicious link that, once a user authenticates with their SAML provider, could post the user’s cookies to an…
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High 7.5
Unexpected input to Create Channel Subscription endpoint causes DoS in Mattermost Confluence Plugin
Mattermost Confluence Plugin version <1.5.0 fails to handle unexpected request body which allows attackers to crash the plugin via constant hit to create channel subscription endpoint with an invalid request body.
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High 7.2
Unauthenticated Channel Subscription Edit in Mattermost Confluence Plugin
Mattermost Confluence Plugin version <1.5.0 fails to enforce authentication of the user to the Mattermost instance which allows unauthenticated attackers to edit channel subscriptions via API call to the edit channel subscription endpoint.
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High 7.5
Unexpected input to Update Channel Subscription endpoint causes DoS in Mattermost Confluence Plugin
Mattermost Confluence Plugin version <1.5.0 fails to handle unexpected request body which allows attackers to crash the plugin via constant hit to update channel subscription endpoint with an invalid request body.
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High 7.2
Unauthenticated Channel Subscription Creation in Mattermost Confluence Plugin
Mattermost Confluence Plugin version <1.5.0 fails to check the authorization of the user to the Mattermost instance which allows attackers to create a channel subscription without proper authorization via API call to the create channel subscription endpoint.
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High 7.5
Bypassing MFA Enforcement on Plugin Endpoints
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8, 10.5.x <= 10.5.0 fail to enforce MFA on plugin endpoints, which allows authenticated attackers to bypass MFA protections via API requests to plugin-specific routes.
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High 8.2
Domain Restriction Bypass on Registration
Mattermost versions 10.0.x <= 10.0.1, 10.1.x <= 10.1.1, 9.11.x <= 9.11.3, 9.5.x <= 9.5.11 fail to properly validate email addresses which allows an unauthenticated user to bypass email domain restrictions via carefully crafted input on email registration.
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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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High 8.1
Timing attack during remote cluster token comparison when shared channels are enabled
Mattermost versions 9.8.x <= 9.8.0, 9.7.x <= 9.7.4, 9.6.x <= 9.6.2 and 9.5.x <= 9.5.5, when shared channels are enabled, fail to use constant time comparison for remote cluster tokens which allows an attacker to retrieve the remote cluster token via a timing …
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High 8.8
Mattermost versions 8.1.x before 8.1.10, 9.2.x before 9.2.6, 9.3.x before 9.3.2, and 9.4.x before 9.4.3 fail to correct…
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High 7.1
Mattermost version 2.10.0 and earlier fails to sanitize deeplink paths, which allows an attacker to perform CSRF attack…
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High 7.3
Reflected client side path traversal leading to CSRF in Playbooks
Mattermost fails to validate if a relative path is passed in /plugins/playbooks/api/v0/telemetry/run/<telem_run_id> as a telemetry run ID, allowing an attacker to use a path traversal payload that points to a different endpoint leading to a CSRF attack.
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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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High 8.1
Lack of server certificate validation in websockets connection
Mattermost iOS app fails to properly validate the server certificate while initializing the TLS connection allowing a network attacker to intercept the WebSockets connection.
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High 7.2
User password logged in audit logs
Mattermost fails to redact from audit logs the user password during user creation and the user password hash in other operations if the experimental audit logging configuration was enabled (ExperimentalAuditSettings section in config).
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High 7.3
Stored XSS via SVG attachment on Boards
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.