Vulnerability DatabaseCVE-2026-6673
Mend.io Vulnerability Database
The largest open source vulnerability database
What is a Vulnerability ID?
New vulnerability? Tell us about it!
CVE-2026-6673
Published:June 22, 2026
Updated:August 04, 2026
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
Affected Packages
github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0+incompatible <v10.11.18+incompatible
Fix Suggestion:
Update to version v10.11.18+incompatible
github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.5.1 <v11.5.6+incompatible
Fix Suggestion:
Update to version v11.5.6+incompatible
github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.6.1-rc1 <v11.6.3+incompatible
Fix Suggestion:
Update to version v11.6.3+incompatible
Related Resources (3)
https://mattermost.com/security-updates
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6673.json
https://nvd.nist.gov/vuln/detail/CVE-2026-6673
Do you need more information?
Contact Us
CVSS v4
Base Score:
5.9
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.4
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Missing Authentication for Critical Function
CWE-306
EPSS
Base Score:
0.30