CVE-2026-6342

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CVSS 3.1

4.3 medium

EPSS

<1%p5

Published

May 18, 2026 (May 18, 2026)

Modified

Jun 17, 2026

Description

Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to appropriately check for valid namespaces which allows plugin users to create subscriptions to groups that were not whitelisted via creating groups that share the same prefix as a whitelisted group. Mattermost Advisory ID: MMSA-2026-00601

Vendors: mattermost
Products: mattermost server
Weakness: CWE-863
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

NVD CVE.org GitHub PoCs EPSS (0.2%)

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