71 matches found
CVE-2026-3117
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...
CVE-2026-6342
Mattermost 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 to groups that were not whitelisted via creating groups that share the same prefix as a whitelisted group. Mattermost Advisory ID:...
CVE-2026-6343
Mattermost 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 permissions to access public playbooks via /get.. Mattermost Advisory ID: MMSA-2026-00591...
Mattermost Server 10.11.x < 10.11.17 / 11.5.x < 11.5.5 / 11.6.x < 11.6.2 Improper Authorization (MMSA-2026-00629)
The version of Mattermost Server installed on the remote host is affected by a vulnerability as referenced in the MMSA-2026-00629 advisory. - Mattermost Server fails to validate team-level runcreate permission against the target team when creating a playbook run which allows an authenticated team...
EUVD-2026-31646
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 filter nil elements from outgoing webhook attachment payloads before processing, which allows an authenticated user to cause a denial of service server process termination via a crafted webhook...
CVE-2026-3473
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 validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs...
CVE-2026-4635 Persistent notification timing attack causing server denial of service
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 archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting...
CVE-2026-4635
Mattermost (versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x
PT-2026-42747
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 archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting...
CVE-2026-4858
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 via path traversal in integration action...
PT-2026-42404
Mattermost 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 authenticated team member to create runs in teams where they lack permission via specifying a different team ID in the run creation API reques...
GHSA-M79Q-8QF5-V622 Mattermost doesn't check public/private permissions
Mattermost 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 permissions to access public playbooks via /get.. Mattermost Advisory ID: MMSA-2026-00591...
Mattermost doesn't verify channel membership when processing AI-assisted message rewrites
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...
GHSA-JP3F-X449-4Q75 Mattermost doesn't enforce client identity binding during the OAuth authorization code redemption flow
Mattermost 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 allows an authenticated OAuth client to redeem authorization codes issued to a different client via a crafted token exchange request.. Mattermo...
Mattermost does not verify remote cluster channel access when processing shared channel membership removals
Mattermost 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 membership removal requests during shared channel membership sync, which allows a malicious remote cluster to remove any user from any channel,...
GHSA-CJM8-JXPW-G43M Mattermost doesn't validate 7zip archive structure before processing
Mattermost 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 authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder...
Mattermost doesn't enforce client identity binding during the OAuth authorization code redemption flow
Mattermost 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 allows an authenticated OAuth client to redeem authorization codes issued to a different client via a crafted token exchange request.. Mattermo...
CVE-2026-6343
Mattermost 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 permissions to access public playbooks via /get.. Mattermost Advisory ID: MMSA-2026-00591...
CVE-2026-3471
Mattermost 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 a malicious server owner to repeated crash the application via calling window.open'javascript:alert';. Mattermost Advisory ID: MMSA-2026-00...
CVE-2026-6333
Mattermost 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 allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost...