Mattermost

613 CVEs across 27 Mattermost products. Browse Mattermost vulnerabilities, severities, and proof-of-concept exploits.

Mattermost products with known CVEs

ProductCVEs
Mattermost Server455
Mattermost429
Mattermost Desktop30
Mattermost Mobile21
Confluence14
Mattermost Confluence Plugin14
Mattermost Desktop3
Focalboard2
Legal Hold2
Mattermost App Framework2
Mattermost Boards2
Mattermost Boards2
Mattermost Playbooks2
Ms Teams2
Playbooks2
Zoom2
Channel Export1
Github.com/mattermost/mattermost/server/public1
Google Drive1
Mattermost GitHub Plugin1
Mattermost Google Drive Plugin1
Mattermost iOS App1
Mattermost Mobile1
Mattermost Packages1
Mattermost Plugins1
Mattermost Plugins1
Playbooks Plugin1
Mattermost CVEs — newest first (page 1 of 7)
CVESeverityScorePublishedSummary
CVE-2026-14298Medium6.52026-08-13Mattermost 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 properly limit resource consumption when processing certa…
CVE-2026-7521Medium5.52026-07-28Mattermost versions 11.8.x <= 11.8.0, 11.7.x <= 11.7.3, 11.6.x <= 11.6.5, 10.11.x <= 10.11.20 fail to verify file deletion path which allows an admin with SAML…
CVE-2026-10819Medium6.52026-07-27Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number of frames and enforce the file size cap…
CVE-2026-10600Medium4.32026-07-27Mattermost versions 11.8.x <= 11.8.0, 11.7.x <= 11.7.3, 11.6.x <= 11.6.5, 10.11.x <= 10.11.20 fail to bound the time and resource consumption of server-side do…
CVE-2026-9602Medium6.52026-07-17Mattermost Desktop App versions <=6.2 6.0.2 5.6.13.0 fail to validate payloads sent from the Mattermost Web App to the Desktop App which allows a malicious ser…
CVE-2026-8075Medium6.52026-07-17Mattermost Desktop App versions <=6.2 5.5.13 6.0.2.0 fail to properly null check when checking for headers in the Mattermost Desktop App which allows any user…
CVE-2026-9824Medium4.32026-07-13Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to check the manage_shared_channels permission in the /share-channel autocompl…
CVE-2026-9820Low3.82026-07-13Mattermost versions 11.7.x <= 11.7.2, 10.11.x <= 10.11.19 fail to sanitize team objects returned by the scheme teams endpoint, which allows a user with the Use…
CVE-2026-6541Medium4.32026-07-13Mattermost versions 11.7.x <= 11.7.1, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict metric configuration changes to the playbook being saved, which al…
CVE-2026-9708Medium4.92026-07-13Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate that an assigned incoming webhook user has access to the target te…
CVE-2026-9597Medium5.42026-07-13Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4 fail to verify whether a guest account is deactivated before creating a session in the magic-link token…
CVE-2026-9571Medium5.92026-07-13Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allow…
CVE-2026-6850Medium6.52026-07-13Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate the length and content of message attachment field values, which a…
CVE-2026-10106Medium6.52026-07-13Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify that the channel referenced in an action cookie matches the channel…
CVE-2026-10103Medium4.32026-07-13Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify post ownership in the shared channel inbound sync handler, which all…
CVE-2026-10085Medium5.42026-07-13Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to restrict the group_constrained channel flag to public and private channels…
CVE-2026-9699Medium6.82026-06-26Mattermost Plugins versions <=11.6 10.18.11 11.3.6 11.6.5.0 fail to sanitize error responses from the OpenAI API before logging, which allows a user with acces…
CVE-2026-4339Medium6.52026-06-26Mattermost versions 10.11.x <= 10.11.18, 11.6.x <= 11.6.3, 11.5.x <= 11.5.6 fail to validate attachment URLs against internal or private IP ranges in the Matte…
CVE-2026-3472Low3.52026-06-26Mattermost versions 10.11.x <= 10.11.18, 11.6.x <= 11.6.3, 11.5.x <= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result…
CVE-2026-13426Medium5.42026-06-26The Mattermost Go module github.com/mattermost/mattermost/server/public versions < v0.1.22 fail to validate path parameters when constructing API route paths w…
CVE-2026-2299Medium4.22026-06-25The Mattermost Google Drive plugin before version 1.1.0 fails to validate channel membership in the file creation endpoint, allowing authenticated users with a…
CVE-2026-8823Low3.82026-06-22Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administra…
CVE-2026-9162Medium4.32026-06-22Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to invalidate cached authentication state for active WebSock…
CVE-2026-8074Low3.82026-06-22Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to enforce bot-specific permission checks on the user active status endpoint, which allows a Use…
CVE-2026-6673Medium6.42026-06-22Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allow…
CVE-2026-6062Medium6.42026-06-22Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription be…
CVE-2026-5139Medium5.42026-06-22Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultIn…
CVE-2026-8683Medium6.52026-06-15Mattermost Desktop App versions <=6.1 5.5.13.0 fail to account for attempting to open extremely long URLs in the Mattermost Desktop App which allows a maliciou…
CVE-2026-6517Medium6.32026-06-15Mattermost Desktop App versions <=6.1 5.5.13.0 fail to restrict the allow list of domains to which NTLM credentials were forwarded to in the Mattermost Desktop…
CVE-2026-7387High8.82026-06-12Mattermost 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…
CVE-2026-7184Medium6.52026-06-12Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows…
CVE-2026-6961High7.62026-06-12Mattermost 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 feder…
CVE-2026-6739Medium6.72026-06-12Mattermost 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 fail to require system-level permission when patching protecte…
CVE-2026-6689Medium4.32026-06-12Mattermost 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 Fail to enforce PermissionInviteUser when setting AllowOpenInv…
CVE-2026-6046Medium5.32026-06-12Mattermost 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 fail to validate that a username returned during bot registrat…
CVE-2026-3433Medium4.32026-06-12Mattermost 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 fail to restrict role_updated websocket event broadcasts to me…
CVE-2026-6957High8.02026-05-27Mattermost Plugins versions <=1.1.5 fail to sanitize filenames received from federated peers before using them to construct export destination paths, which all…
CVE-2026-4915Medium6.52026-05-25Mattermost 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 filter nil elements from outgoing webhook attachment payl…
CVE-2026-28735Medium5.42026-05-22Mattermost 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 validate the OAuth token scope on the callback which allo…
CVE-2026-5755Medium6.52026-05-22Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.2, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the TIFF IFD offset in the ima…
CVE-2026-5740High7.52026-05-22Mattermost 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…
CVE-2026-5308Medium4.92026-05-22Mattermost 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 enforce request body size limits on plugin HTTP endpoints…
CVE-2026-4646Medium4.32026-05-22Mattermost 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 validate user-supplied input in API request handlers whic…
CVE-2026-4635Medium6.52026-05-22Mattermost 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 archive the channel before removing persistent notificati…
CVE-2026-3636Medium4.32026-05-22Mattermost 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 sanitize team member data when returned via API to users…
CVE-2026-3473Medium5.92026-05-22Mattermost 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 validate file ownership and access control, which allows…
CVE-2026-4858High8.02026-05-21Mattermost 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…
CVE-2026-22880Medium6.12026-05-21Mattermost Mobile Apps versions <=2.37 11.4 2.0.37 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to properly validate the SSO authentication callback origin which allow…
CVE-2026-4055Medium4.32026-05-21Mattermost versions 11.5.x <= 11.5.1 fail to validate team-level run_create permission against the target team when creating a playbook run which allows an aut…
CVE-2026-6347High7.62026-05-18Mattermost 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 whic…
CVE-2026-6346High8.72026-05-18Mattermost 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 pa…
CVE-2026-6345Medium6.52026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker…
CVE-2026-6343Medium4.32026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to check public/private permissions which allows members without these permiss…
CVE-2026-6339Medium4.32026-05-18Mattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an authent…
CVE-2026-6333Low3.52026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allo…
CVE-2026-5163Medium6.52026-05-18Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to r…
CVE-2026-4643Low3.52026-05-18Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent server-rendered content from closing an underlying application view in the Mattermost Desk…
CVE-2026-4286Low3.12026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to check if {{team_id}} was being changed when updating playbooks, allowing users with only {{Ma…
CVE-2026-3471Medium6.52026-05-18Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows…
CVE-2026-3117Medium6.52026-05-18Mattermost 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 n…
CVE-2026-28732Medium4.32026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to enforce slash command trigger-word uniqueness during command updates which…
CVE-2026-6342Medium4.32026-05-18Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to appropriately check for valid namespaces which allows plugin users to create subscriptions…
CVE-2026-6341Medium4.32026-05-18Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to have API-level checks on which groups the user can create issues or attach comments to whic…
CVE-2026-6340Medium4.32026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authentic…
CVE-2026-6334Low3.12026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to enforce client identity binding during the OAuth authorization code redemption flow which all…
CVE-2026-4273Low3.72026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate that the RefreshedToken differs from the original invite token during remote cluster…
CVE-2026-3637Medium4.32026-05-18Mattermost 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…
CVE-2026-3495Low3.82026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to escape some variables that could contain malicious content during error page composition whic…
CVE-2026-2325Medium4.32026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to limit the size of the request body on the start meeting API endpoint, which…
CVE-2026-28759Medium4.32026-05-18Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate that a remote cluster has access to a channel before processing me…
CVE-2026-4054Medium4.32026-05-15Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacke…
CVE-2026-4053Low3.12026-05-15Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user t…
CVE-2026-3590Medium6.52026-04-15Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link…
CVE-2026-28741Medium6.82026-04-15Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to validate CSRF tokens on an authentication endpoint which…
CVE-2026-27769Low2.72026-04-15Mattermost 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…
CVE-2026-24661Low3.72026-04-09Mattermost Plugins versions <=2.1.3.0 fail to limit the request body size on the {{/changes}} webhook endpoint which allows an authenticated attacker to cause…
CVE-2026-21388Low3.72026-04-09Mattermost Plugins versions <=2.3.1 fail to limit the request body size on the {{/lifecycle}} webhook endpoint which allows an authenticated attacker to cause…
CVE-2026-3524High8.82026-04-06Mattermost Plugin Legal Hold versions <=1.1.4 fail to halt request processing after a failed authorization check in ServeHTTP which allows an authenticated att…
CVE-2026-28736Medium4.32026-04-03** UNSUPPORTED WHEN ASSIGNED ** Focalboard version 8.0 fails to validate file ownership when serving uploaded files. This allows an authenticated attacker who…
CVE-2026-25773High8.12026-04-03** UNSUPPORTED WHEN ASSIGNED ** Focalboard version 8.0 fails to sanitize category IDs before incorporating them into dynamic SQL statements when reordering cat…
CVE-2026-3116Medium4.92026-03-26Mattermost Plugins versions <=11.4 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to validate incoming request size which allows an authenticated attacker to cause servi…
CVE-2026-3115Medium4.32026-03-26Mattermost 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 apply view restrictions when retrieving group member IDs…
CVE-2026-3114Medium6.52026-03-26Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to validate decompressed archive entry sizes during file ext…
CVE-2026-3113Medium5.02026-03-26Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to set permissions on downloaded bulk export which allows ot…
CVE-2026-3112Medium6.82026-03-26Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to validate Advanced Logging file target paths which allows…
CVE-2026-3109Low2.22026-03-26Mattermost Plugins versions <=11.4 10.11.11.0 fail to validate webhook request timestamps which allows an attacker to corrupt Zoom meeting state in Mattermost…
CVE-2026-3108High8.02026-03-26Mattermost 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 comman…
CVE-2026-4274Medium5.42026-03-26Mattermost 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 restrict team-level access when processing membership syn…
CVE-2026-27659Medium4.62026-03-25Mattermost 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 properly validate CSRF tokens in the /api/v4/access_contr…
CVE-2026-27656Medium5.72026-03-25Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to properly validate user identity in the OpenID {{IsSameUse…
CVE-2026-26233Medium4.32026-03-25Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to rate limit login requests which allows unauthenticated re…
CVE-2026-20719Medium4.32026-03-25Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to prevent rendering of external SVGs on link embeds which a…
CVE-2026-2454Medium5.82026-03-16Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to handle incorrectly reported array lengths which allows malicious user to ca…
CVE-2026-26230Low3.82026-03-16Mattermost versions 10.11.x <= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrator…
CVE-2026-1629Medium4.32026-03-16Mattermost versions 10.11.x <= 10.11.10 Fail to invalidate cached permalink preview data when a user loses channel access which allows the user to continue vie…
CVE-2026-26304Medium4.32026-03-16Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthori…
CVE-2026-2455Medium4.32026-03-16Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to canonicalize IPv4-mapped IPv6 addresses before reserved IP validation which…
CVE-2026-24692Medium4.32026-03-16Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly enforce read permissions in search API endpoints which allows gues…
CVE-2026-22545Low3.12026-03-16Mattermost versions 10.11.x <= 10.11.10 fail to validate user's authentication method when processing account auth type switch which allows an authenticated at…
CVE-2026-21386Medium4.32026-03-16Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to use consistent error responses when handling the /mute command which allows…