Is CVE-2026-20796 actively exploited?

CVE-2026-20796 has no public evidence of in-the-wild exploitation as of 2026-02-23.

What is the CVSS score for CVE-2026-20796?

CVE-2026-20796 has a CVSS score of 3.1 (LOW severity). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N.

How do I patch CVE-2026-20796?

Patch guidance is available from mattermost security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-20796.

Which products are affected by CVE-2026-20796?

1 product: mattermost mattermost server.

CVE-2026-20796 - remediation guidance & executive summary

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 Metrics

Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
Attack Vector: network
Complexity: high
Privileges: low
User Action: none
Scope: unchanged
Confidentiality: low
Integrity: none
Availability: none
Weaknesses: CWE-367

Metadata

Primary Vendor: MATTERMOST
Published: 2/13/2026
Last Modified: 2/23/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

mattermost : mattermost_server

Remediation Guidance

Executive Summary

Cite this page

CVE-2026-20796. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2026-20796

View on NIST NVD

CVE-2026-20796 vulnerability