BaseFortify

Publication date: 2025-12-17

Last updated on: 2025-12-29

Assigner: Mattermost, Inc.

Description

Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, 10.11.x <= 10.11.6 fail to check WebSocket request field for proper UTF-8 format, which allows attacker to crash Calls plug-in via sending malformed request.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-12-17

Last Modified

2025-12-29

Generated

2026-07-06

AI Q&A

2025-12-17

EPSS Evaluated

2026-07-05

NVD

CVE-2025-12689

Affected Vendors & Products

Vendor	Product	Version / Range
mattermost	mattermost_server	From 10.11.0 (inc) to 10.11.7 (exc)
mattermost	mattermost_server	From 10.12.0 (inc) to 10.12.3 (exc)
mattermost	mattermost_server	From 11.0.0 (inc) to 11.0.5 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-1287	The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type.

Attack-Flow Graph

Executive Summary

This vulnerability exists in Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, and 10.11.x <= 10.11.6, where the software fails to check the WebSocket request field for proper UTF-8 format. This flaw allows an attacker to send a malformed WebSocket request that can crash the Calls plug-in.

Impact Analysis

The impact of this vulnerability is a denial of service condition where an attacker can crash the Calls plug-in by sending malformed WebSocket requests. This can disrupt communication features relying on the Calls plug-in, potentially affecting availability.

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