CVE-2025-11777

Name: CVE-2025-11777
Creator: NVD / NIST
Published: 2025-11-13T18:15:49.393+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.3/10EPSS 0.16%

Last modified Jun 17, 2026

CVE-2025-11777 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata and channel membership information from other teams via the API endpoint. EPSS estimates a 0.16% chance of exploitation in the next 30 days.

Description

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata and channel membership information from other teams via the API endpoint

Metrics

CVSS 3.1

4.3/10

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

EPSS Probability

0.16%

5.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-863

Affected Software

Vendor	Product	Versions
Mattermost	Mattermost Server	>= 10.5.0, < 10.5.12
Mattermost	Mattermost Server	>= 10.11.0, < 10.11.4

References

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

Timeline

Published: Nov 13, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-11777?

How severe is CVE-2025-11777?

CVE-2025-11777 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.

How do I fix CVE-2025-11777?

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-2025-11777?

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

Scan your code now

Source: NVD / NIST