CVE-2025-11777
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-11-13

Last updated on: 2025-11-17

Assigner: Mattermost, Inc.

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
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Meta Information
Published
2025-11-13
Last Modified
2025-11-17
Generated
2026-06-16
AI Q&A
2025-11-13
EPSS Evaluated
2026-06-15
NVD
CVE-2025-11777
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
mattermost mattermost_server From 10.5.0 (inc) to 10.5.12 (exc)
mattermost mattermost_server From 10.11.0 (inc) to 10.11.4 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
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Executive Summary

This vulnerability in Mattermost versions 10.11.x <= 10.11.3 and 10.5.x <= 10.5.11 involves improper validation of team membership permissions in the Add Channel Member API. It allows users from one team to access user metadata and channel membership information from other teams through the API endpoint.

Impact Analysis

The vulnerability can lead to unauthorized access where users from one team can view user metadata and channel membership details of other teams, potentially exposing sensitive information and violating privacy boundaries within the Mattermost platform.

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