Is CVE-2026-6341 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-6341 being exploited in the wild.

How severe is CVE-2026-6341?

Medium severity, with a CVSS score of 4.3, published 18 May 2026.

Which products and versions are affected?

Mattermost Plugins <=11.5, 11.1.5, 10.13.11, 11.3.4.0.

Is there a fix for CVE-2026-6341?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-6341 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-6341?

Check whether you run Mattermost Plugins at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-6341: Mattermost Plugins incorrect authorization in group API requests

Q: Which products and versions are affected?

Mattermost Plugins <=11.5, 11.1.5, 10.13.11, 11.3.4.0.

Q: Is there a fix for CVE-2026-6341?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

Q: How is CVE-2026-6341 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-6341?

Check whether you run Mattermost Plugins at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-6341 · Severity: medium · CVSS 4.3 · Published 2026-05-18

Mattermost Plugins, which extend the functionality of the Mattermost collaboration platform, contain a security flaw in how they handle user permissions for specific groups. An authenticated user who belongs to multiple groups can bypass restrictions to create issues or post comments in groups that should be locked or restricted. This could lead to unauthorized data entry or communication within sensitive, restricted project areas.

Technologies: Mattermost Plugins. Vendors: Mattermost.

Quick answers

Is CVE-2026-6341 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-6341 being exploited in the wild.
How severe is CVE-2026-6341?: Medium severity, with a CVSS score of 4.3, published 18 May 2026.
Which products and versions are affected?: Mattermost Plugins <=11.5, 11.1.5, 10.13.11, 11.3.4.0.
Is there a fix for CVE-2026-6341?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-6341 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-6341?: Check whether you run Mattermost Plugins at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An incorrect authorization vulnerability (CWE-863) exists in Mattermost Plugins versions up to 11.5, 11.1.5, 10.13.11, and 11.3.4.0. The software fails to implement sufficient API-level validation to verify if a user has the appropriate permissions for a specific group before allowing issue creation or comment attachment. An attacker with low-privileged authenticated access who is a member of multiple groups can bypass UI-level restrictions by sending direct API requests to interact with locked groups. This allows for unauthorized integrity-impacting actions within the collaboration environment.

Affected products

Mattermost Mattermost Plugins <=11.5, 11.1.5, 10.13.11, 11.3.4.0

Timeline

2026-05-18: disclosed
2026-05-18: advisory

References

https://mattermost.com/security-updates

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