CVE-2026-6673

MEDIUM EPSS 7.5%
Published Jun 22, 20261w ago · Modified Jun 23, 20266d ago
6.4 CVSS 3.1
Medium
Find Similar
Published Jun 22, 2026 1w ago
Last Modified Jun 23, 2026 6d ago

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

CVSS Details

Base Score
6.4
Exploitability
1.2
Impact
5.2
Vector string
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:H
Attack Vector Network
Attack Complexity High
Privileges Required Low
User Interaction Required
Scope Unchanged
Confidentiality None
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
7.5% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-306 Missing Authentication for Critical Function Authentication

Affected Products 4

VendorProductVersionRange
mattermostmattermost_server*≥10.11.0  –  <10.11.18
mattermostmattermost_server*≥11.5.0  –  <11.5.6
mattermostmattermost_server*≥11.6.0  –  <11.6.3
mattermostmattermost_server*≥11.7.0  –  <11.7.1

References 1

  • mattermost.com https://mattermost.com/security-updates
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.