PT-2026-51304 · Mattermost · Mattermost

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Published

2026-06-22

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Updated

2026-06-22

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CVE-2026-5139

CVSS v3.1

5.4

Medium

VectorAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to overwrite the global default GitLab instance configuration via the {{/gitlab connect }} slash command.. Mattermost Advisory ID: MMSA-2026-00644

Fix

Missing Authorization

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Weakness Enumeration

Related Identifiers

CVE-2026-5139

Affected Products

Mattermost