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VULNERABILITIES

CVE-2026-6673 Details

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.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:6.4 MEDIUMVector:CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:H

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://mattermost.com/security-updates [email protected]Vendor Advisory

Weakness Enumeration

CWE-IDCWE NameSource
CWE-306Missing Authentication for Critical Function[email protected]

Affected Products

ProductVersions
mattermost mattermost server
>= 10.11.0, < 10.11.18
>= 11.5.0, < 11.5.6
>= 11.6.0, < 11.6.3
>= 11.7.0, < 11.7.1

CPE

  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.

Change History

3 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-6673
NVD Published Date:
Jun 22, 2026
NVD Last Modified:
Jun 23, 2026
Source:
[email protected]