CVE-2026-6673

MediumCVSS 6.4/10Last modified Jun 23, 2026

Description

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 authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to /ac/installed during the pending-install window.. Mattermost Advisory ID: MMSA-2026-00654

Metrics

CVSS 3.1 6.4/10CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:H

Weakness enumeration

CWE-306

Affected software

No affected versions have been published.

Timeline

Published: Jun 22, 2026
Last modified: Jun 23, 2026
NVD status: Analyzed

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