CVE-2026-20796

Name: CVE-2026-20796
Creator: NVD / NIST
Published: 2026-02-13T11:16:10.28+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

LOWCVSS 3.1/10EPSS 0.20%

Last modified Jun 17, 2026

CVE-2026-20796 is a low-severity vulnerability rated 3.1/10 on the CVSS scale. 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. EPSS estimates a 0.20% chance of exploitation in the next 30 days.

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

Metrics

CVSS 3.1

3.1/10

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

EPSS Probability

0.20%

9.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-367

Affected Software

Vendor	Product	Versions
Mattermost	Mattermost Server	>= 10.11.0, < 10.11.10

References

https://mattermost.com/security-updatesVendor Advisory

Timeline

Published: Feb 13, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-20796?

How severe is CVE-2026-20796?

CVE-2026-20796 has a CVSS score of 3.1/10 (LOW severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-20796?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-20796?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST