CVE-2025-13767 Unauthorized Read Access to Private Channel Posts via Mattermost Jira Plugin

Medium 4.3 Published Updated

An authenticated attacker can read private channel posts and attachments via the Jira plugin due to missing channel membership validation.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2025-13767?

CVE-2025-13767 is a medium-severity missing authorization vulnerability in Mattermost Mattermost Server, published on 24 Dec 2025. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Mattermost versions 11.1.x <= 11.1.0, 11.0.x <= 11.0.5, 10.12.x <= 10.12.3, 10.11.x <= 10.11.7 fails to validate user channel membership when attaching Mattermost posts as comments to Jira issues, which allows an authenticated attacker with access to the Jira plugin to read post content and attachments from channels they do not have access to.

Weakness: CWE-863

Which versions are affected by CVE-2025-13767?

14 open source packages ship an affected version, including github.com/mattermost/mattermost-server, github.com/mattermost/mattermost-server/v5 and github.com/mattermost/mattermost-server/v6. It affects 1 product.

PackageAffectedFixed in
github.com/mattermost/mattermost-server GoFrom 10.11.010.11.8
github.com/mattermost/mattermost-server GoFrom 10.11.010.11.8
github.com/mattermost/mattermost-server GoFrom 10.11.0+incompatible10.11.8+incompatible, 10.12.4+incompatible, 11.0.6+incompatible, 11.1.1+incompatible
github.com/mattermost/mattermost-server GoFrom 10.12.010.12.4
github.com/mattermost/mattermost-server GoFrom 10.12.010.12.4
github.com/mattermost/mattermost-server GoFrom 11.0.011.0.6
8 more packages
github.com/mattermost/mattermost-server GoFrom 11.0.011.0.6
github.com/mattermost/mattermost-server GoFrom 11.1.011.1.1
github.com/mattermost/mattermost-server GoFrom 11.1.011.1.1
github.com/mattermost/mattermost-server/v5 GoAll versionsNone
github.com/mattermost/mattermost-server/v6 GoAll versionsNone
github.com/mattermost/mattermost/server/v8 GoAll versionsNone
github.com/mattermost/mattermost/server/v8 GoAll versions8.0.0-20251121122154-b57c297c6d7
github.com/mattermost/mattermost/server/v8 GoAll versions8.0.0-20251121122154-b57c297c6d7

Products include Mattermost Mattermost Server.

How do I fix CVE-2025-13767?

Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 10.11.8, 10.11.8+incompatible, 10.12.4+incompatible or 11.0.6+incompatible.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2025-13767 being exploited?

There is no known exploitation of CVE-2025-13767 in the wild and no public exploit code.

All Mattermost Mattermost Server vulnerabilities

Sources

Also known as GHSA-fmqf-pmcm-8cx9, GO-2025-4259.

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