CVE-2026-20796

LOW EPSS 9.8%

Published Feb 13, 20264mo ago · Modified Jun 17, 20262w ago

3.1 CVSS 3.1

Low

Published Feb 13, 2026 4mo ago

Last Modified Jun 17, 2026 2w ago

Description

Mattermost versions 10.11.x <= 10.11.9 fail to properly validate channel membership at the time of data retrieval which allows a deactivated user to learn team names they should not have access to via a race condition in the /common_teams API endpoint.. Mattermost Advisory ID: MMSA-2025-00549

CVSS Details

Base Score

3.1

Exploitability

1.6

Impact

1.4

Vector string

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

Attack Vector Network

Attack Complexity High

Privileges Required Low

User Interaction None

Scope Unchanged

Confidentiality Low

Integrity None

Availability None

Threat Intelligence

EPSS Exploit Probability

9.8% percentile

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 1

CWE-367

Affected Products 1

Vendor	Product	Version	Range
mattermost	mattermost_server	*	≥10.11.0 – <10.11.10

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.