GO-2025-4178 CVE-2025-13870 GHSA-58w6-w55x-6wq8

Mattermost fails to validate user permissions in Boards in github.com/mattermost/mattermost

Medium Go

Severity: 4.3 / 10; Medium · CVSS 3.1
Exploit chance (EPSS): 0.22%; Chance of exploitation in the next 30 days. Higher than 12.90% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-284 Improper Access Control; CWE-306 Missing Authentication for Critical Function
Fix: Available; 2 packages have a fixed version

Description

Affected versions

Go

Package	Vulnerable	Fixed in
github.com/mattermost/mattermost	`>= 10.11.0, < 10.11.5`	`10.11.5`
github.com/mattermost/mattermost	`>= 10.5.0, < 10.5.13`	`10.5.13`
github.com/mattermost/mattermost	`>= 10.5.0+incompatible, < 10.5.13+incompatible` `>= 10.11.0+incompatible, < 10.11.5+incompatible`	`10.5.13+incompatible` `10.11.5+incompatible`
github.com/mattermost/mattermost-server	`all versions`	No fix yet
github.com/mattermost/mattermost-server/v5	`all versions`	No fix yet
github.com/mattermost/mattermost-server/v6	`all versions`	No fix yet
github.com/mattermost/mattermost/server/v8	`< 8.0.0-20250905150616-ba86dfc5876b`	`8.0.0-20250905150616-ba86dfc5876b`
github.com/mattermost/mattermost/server/v8	`< 8.0.0-20251212204551-54f2e9b4afd5`	`8.0.0-20251212204551-54f2e9b4afd5`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

github.com/mattermost/mattermost Go → `10.11.5`

go

go get github.com/mattermost/mattermost@v10.11.5 && go mod tidy

github.com/mattermost/mattermost/server/v8 Go → `8.0.0-20250905150616-ba86dfc5876b`

go

go get github.com/mattermost/mattermost/server/v8@v8.0.0-20250905150616-ba86dfc5876b && go mod tidy

Severity breakdown

CVSS 3.1 4.3

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Weakness

CWE-284: Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

How to prevent it

Architecture and Design, Operation: Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

CWE-306: Missing Authentication for Critical Function

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

How to prevent it

Architecture and Design: Divide the software into anonymous, normal, privileged, and administrative areas. Identify which of these areas require a proven user identity, and use a centralized authentication capability. Identify all potential communication channels, or other means of interaction with the software, to ensure that all channels are appropriately protected, including those channels that are assumed to be accessible only by authorized parties. Developers sometimes perform authentication at the primary channel, but open up a secondary channel that is assumed to be private. For example, a login mechanism may be listening on one network port, but after successful authentication, it may open up a second port where it waits for the connection, but avoids authentication because it assumes that only the authenticated party will connect to the port. In general, if the software or protocol allows a single session or user state to persist across multiple connections or channels, authentication and appropriate credential management need to be used throughout.
Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Architecture and Design: Where possible, avoid implementing custom, "grow-your-own" authentication routines and consider using authentication capabilities as provided by the surrounding framework, operating system, or environment. These capabilities may avoid common weaknesses that are unique to authentication; support automatic auditing and tracking; and make it easier to provide a clear separation between authentication tasks and authorization tasks. In environments such as the World Wide Web, the line between authentication and authorization is sometimes blurred. If custom authentication routines are required instead of those provided by the server, then these routines must be applied to every single page, since these pages could be requested directly.
Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator [REF-45].
Implementation, System Configuration, Operation: When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data [REF-1297] [REF-1298] [REF-1302].

References

Advisories

Packages

github.com/mattermost/mattermost

Timeline

Dec 2, 2025 Published
Oct 18, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-xmfh-3ccg-c9fx Mattermost has an Incorrect Authorization issue	Low	Also affects github.com/mattermost/mattermost-server
GHSA-h998-hxxj-8q83 Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation	Medium	Also affects github.com/mattermost/mattermost-server
GHSA-g5vr-6pgg-74qv Mattermost doesn't enforce bot-specific permission checks on the user active status endpoint	Low	Also affects github.com/mattermost/mattermost-server
GHSA-jqgv-39mg-7c2r Mattermost doesn't authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret	Medium	Also affects github.com/mattermost/mattermost-server
GHSA-mxq2-5jpg-7474 Mattermost doesn't validate channel ownership of an existing subscription before applying edits	Medium	Also affects github.com/mattermost/mattermost-server
GHSA-2g8v-grq3-hq2g Mattermost doesn't enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler	Medium	Also affects github.com/mattermost/mattermost-server
GHSA-6hxm-w4hv-vgvw Mattermost doesn't require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints	High	Also affects github.com/mattermost/mattermost-server
GHSA-9p44-r552-4wp9 Mattermost doesn't sanitize the Remote Cluster API response on PATCH operations	Medium	Also affects github.com/mattermost/mattermost-server

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