Search vulnerabilities

Use the Query Builder to create your own search query, or check out the documentation to learn the search syntax.

Results 664

Export CSV
CVE-2026-13417

Boards plugin denial of service via unvalidated block fields.properties

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 the type of `fields.properties` on block creation which allows an authenticated user with editor access to a board to crash the Boards plugin worker and trigger a denial of service via a child block whose `fields.properties` is a non-object value. Mattermost Advisory ID: MMSA-2026-00710

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-14259

Board archive import bypasses team board creation permissions

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 enforce board creation permissions when importing archive files which allows an authenticated non-guest team member to create Open or Private boards despite administrator restrictions via importing a crafted .boardarchive file. Mattermost Advisory ID: MMSA-2026-00712

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-14344

Inconsistent authorization checks in Mattermost Boards endpoints

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 enforce the board-creation permission which allows an unauthorized authenticated user to create boards via the board duplicate, boards-and-blocks, and archive-import endpoints.. Mattermost Advisory ID: MMSA-2026-00715

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-15814

Uploading a crafted image causes excessive memory allocation in the Mattermost Server

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 limit the amount of memory allocated when decoding uploaded image files which allows an authenticated user to cause excessive server memory consumption and potential denial of service via uploading a specially crafted image as a profile picture, channel file attachment, team icon, or custom brand image. Mattermost Advisory ID: MMSA-2026-00719

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-5132

Unbounded zlib decompression in Calls SDP WebSocket messages

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 limit size of unpacked SDP messages compressed with zlib, which allows attacker to deny service or crash server via sending many SDP messages that unpack to large size.. Mattermost Advisory ID: MMSA-2026-00643

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-8821

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 channel via the run owner field.. Mattermost Advisory ID: MMSA-2026-00677

CVSS 3.1 · 7.1 High EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-9812

Missing property field ownership validation in Playbooks run property update endpoint

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 that a property field belongs to the specified run before updating its value which allows an authenticated user with run property-management access to crash the Playbooks plugin via a REST request referencing a property field that belongs to a different run. Mattermost Advisory ID: MMSA-2026-00684

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-14298

Boards archive import endpoint allows resource exhaustion via zip bomb and file size limit bypass in Mattermost

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 limit decompressed content size and enforce the configured maximum file size in the Boards archive import handler, which allows an authenticated user to cause memory exhaustion or unbounded disk consumption via a crafted .boardarchive file uploaded to the import endpoint.. Mattermost Advisory ID: MMSA-2026-00713

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-75587

Plaintext pre-auth secret exposure via Desktop App diagnostics report

Mattermost Desktop App versions <=6.2 6.2.2.0 fail to redact the pre-auth secret when generating a diagnostics report, which allows a local attacker with access to a user's diagnostics report or log files to obtain the plaintext pre-auth secret configured for a connected server via inspecting the Server Connectivity (Step-3) diagnostics output. Mattermost Advisory ID: MMSA-2026-00716

CVSS 3.1 · 3.6 Low EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Desktop
CVE-2026-9816

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 via POST /api/v2/boards/{boardID}/members and POST /api/v2/teams/{teamID}/archive/import.. Mattermost Advisory ID: MMSA-2026-00685

CVSS 3.1 · 8.3 High EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-9859

Mattermost Boards plugin didn’t enforce role-based authorization on board channel link allowing board editors to expose boards to arbitrary channels

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to enforce PermissionManageBoardRoles on the channelId field of the batch endpoint, which allows an authenticated board editor to relink any board they can edit to an arbitrary channel via a crafted PATCH request. Mattermost Advisory ID: MMSA-2026-00686

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-9693

Mattermost thread memberships persist after team removal, exposing private channel thread metadata on re-invite

Mattermost versions 10.11.x <= 10.11.20, 11.7.x <= 11.7.5 Mattermost fails to remove thread membership records when a user is removed from or leaves a team, which allows a previously removed user who is later re-invited to the team to view private channel thread root post content and metadata via the team threads API.. Mattermost Advisory ID: MMSA-2026-00682

CVSS 3.1 · 3.5 Low EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-16048

Channel member roles accept out-of-scope roles

Mattermost versions 11.8.x <= 11.8.2, 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to restrict channel member role assignment to channel-scoped roles which allows a channel administrator to gain additional channel permissions via the channel member roles API.. Mattermost Advisory ID: MMSA-2026-00697

CVSS 3.1 · 6.3 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-16047

Board channel linking without read channel permission validation

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to validate that users have read access to a channel before linking a board to it, which allows an authenticated attacker to discover the membership of private channels on the same team via creating, patching, importing, or bulk-creating boards with an arbitrary channelId. Mattermost Advisory ID: MMSA-2026-00674

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-16046

Missing run-state validation on finished playbook runs

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to enforce run-state validation on write operations for finished playbook runs which allows a run participant to modify status, checklists, retrospective content, ownership, and participants on completed runs via REST and GraphQL API requests. Mattermost Advisory ID: MMSA-2026-00675

CVSS 3.1 · 3.5 Low EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-16045

Delegated OAuth tokens could revoke unrelated OAuth application authorizations

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 Mattermost failed to restrict OAuth deauthorization and personal access token management endpoints to direct user sessions, which allowed an OAuth app with a delegated user token to revoke the user's authorizations or tokens for other integrations via account-management endpoints.. Mattermost Advisory ID: MMSA-2026-00704

CVSS 3.1 · 2.7 Low EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-16044

Insufficient validation of guest board admin privileges on archive import

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID: MMSA-2026-00672

CVSS 3.1 · 3.9 Low EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-15754

Missing per-channel team-scope check in ABAC access control policy unassign allows cross-team policy removal

Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718

CVSS 3.1 · 4.2 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-10527

Boards plugin retains Board Admin rights for users demoted to System Guest

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Advisory ID: MMSA-2026-00691

CVSS 3.1 · 6.3 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server
CVE-2026-10080

Boards plugin panics on WebSocket command with non-string field types

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to validate WebSocket command field types which allows an authenticated user to crash the plugin process and deny service to all Boards users via a custom_focalboard_SUBSCRIBE_TEAM message with a non-string teamId.. Mattermost Advisory ID: MMSA-2026-00687

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Vendors
Mattermost
Products
Mattermost Mattermost Server