CVE-2024-9155

Insufficient Authorization On Unlinked Channel Files

Mattermost versions 9.10.x <= 9.10.1, 9.9.x <= 9.9.2, 9.5.x <= 9.5.8 fail to limit access to channels files that have not been linked to a post which allows an attacker to view them in channels that they are a member of.

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-9081

IDOR in board file download allows any user to download any file by UUID

Mattermost versions 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate access controls which allows any authenticated user to download sensitive files via board file download endpoint using UUID enumeration

CVSS 3.1 · 3.1 Low EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-9076

Mattermost Server exposes sensitive user credentials during shared channel membership synchronization

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.

CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-9072

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 attacker-controlled URL.

CVSS 3.1 · 7.6 High EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-9084

Open redirect in OAuth login

Mattermost versions 10.5.x <= 10.5.9 fail to properly validate redirect URLs which allows attackers to redirect users to malicious sites via crafted OAuth login URLs

CVSS 3.1 · 3.1 Low EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-9078

Weak cache keys lead to post IDOR and link preview poisoning

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 properly validate cache keys for link metadata which allows authenticated users to access unauthorized posts and poison link previews via hash collision attacks on FNV-1 hashing

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-8023

Path Traversal in Template Upload Allows Uploading Files Outside Target Directory

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fails to sanitize path traversal sequences in template file destination paths, which allows a system admin to perform path traversal attacks via malicious path components, potentially enabling malicious file placement outside intended directories.

CVSS 3.1 · 6.8 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-2527

Improper access control to group information

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-49222

Mattermost Shared Channel Upload Type Validation Bypass

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.

CVSS 3.1 · 6.8 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-49810

Thread summarization allows persistent access to channel

Mattermost versions 10.5.x <= 10.5.8 fail to validate access controls at time of access which allows user to read a thread via AI posts

CVSS 3.1 · 3.5 Low EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-53971

Channel and Team Membership APIs inadvertently allow loss of Member privileges.

Mattermost versions 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate authorization for team scheme role modifications which allows Team Admins to demote Team Members to Guests via the PUT /api/v4/teams/team-id/members/user-id/schemeRoles API endpoint.

CVSS 3.1 · 3.8 Low EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-47870

Team invite ID leaked to team admin with no member invite privileges

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fail to sanitize the team invite ID in the POST /api/v4/teams/:teamId/restore endpoint which allows an team admin with no member invite privileges to get the team’s invite id.

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-36530

Import Path Traversal Enables Unauthorized Unsigned Plugin Installation

Mattermost versions 10.9.x <= 10.9.1, 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate file paths during plugin import operations which allows restricted admin users to install unauthorized custom plugins via path traversal in the import functionality, bypassing plugin signature enforcement and marketplace restrictions.

CVSS 3.1 · 6.8 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-20051

Arbitrary file read via block duplication in Mattermost Boards

Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate input when patching and duplicating a board, which allows a user to read any arbitrary file on the system via duplicating a specially crafted block in Boards.

CVSS 3.1 · 9.9 Critical EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-4128

Mattermost Guest User Information Disclosure Vulnerability

Mattermost versions 10.5.x <= 10.5.4, 9.11.x <= 9.11.13 fail to properly restrict API access to team information, allowing guest users to bypass permissions and view information about public teams they are not members of via a direct API call to /api/v4/teams/{team_id}.

CVSS 3.1 · 3.1 Low EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2024-29215

Slash commands run in channel without channel membership via playbook task commands

Mattermost versions 9.5.x <= 9.5.3, 9.7.x <= 9.7.1, 9.6.x <= 9.6.1, 8.1.x <= 8.1.12 fail to enforce proper access control which allows a user to run a slash command in a channel they are not a member of via linking a playbook run to that channel and running a slash command as a playbook task command.

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed

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Mattermost Server

CVE-2025-4981

Path Traversal Leading to RCE by Any Authenticated Mattermost User

Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to sanitize filenames in the archive extractor which allows authenticated users to write files to arbitrary locations on the filesystem via uploading archives with path traversal sequences in filenames, potentially leading to remote code execution. The vulnerability impacts instances where file uploads and document search by content is enabled (FileSettings.EnableFileAttachments = true and FileSettings.ExtractContent = true). These configuration settings are enabled by default.

CVSS 3.1 · 9.9 Critical EPSS 1.0% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-4573

LDAP Injection in Mattermost Enterprise Edition When Using Active Directory

Mattermost versions 10.7.x <= 10.7.1, 10.6.x <= 10.6.3, 10.5.x <= 10.5.4, 9.11.x <= 9.11.13 fail to properly validate LDAP group ID attributes, allowing an authenticated administrator with PermissionSysconsoleWriteUserManagementGroups permission to execute LDAP search filter injection via the PUT /api/v4/ldap/groups/{remote_id}/link API when objectGUID is configured as the Group ID Attribute.

CVSS 3.1 · 4.1 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-3611

Improper Access Control in Mattermost allows System Managers to view team details despite role restrictions

Mattermost versions 10.7.x <= 10.7.0, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fails to properly enforce access control restrictions for System Manager roles, allowing authenticated users with System Manager privileges to view team details they should not have access to via direct API requests to team endpoints, even when explicitly configured with 'No access' to Teams in the System Console.

CVSS 3.1 · 3.1 Low EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server

CVE-2025-3227

Unauthorized channel member management through playbook runs

Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly enforce channel member management permissions in playbook runs, allowing authenticated users without the 'Manage Channel Members' permission to add or remove users from public and private channels by manipulating playbook run participants when the run is linked to a channel.

CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed

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Mattermost Mattermost Server