BaseFortify

Publication date: 2025-11-14

Last updated on: 2025-11-19

Assigner: Mattermost, Inc.

Description

Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11, 10.12.x <= 10.12.0 fail to validate the relationship between the post being updated and the MSTeams plugin OAuth flow which allows an attacker to edit arbitrary posts via a crafted MSTeams plugin OAuth redirect URL.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-11-14

Last Modified

2025-11-19

Generated

2026-07-06

AI Q&A

2025-11-14

EPSS Evaluated

2026-07-05

NVD

CVE-2025-55073

Affected Vendors & Products

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)
mattermost	mattermost_server	From 10.12.0 (inc) to 10.12.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-306	The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Attack-Flow Graph

Executive Summary

This vulnerability exists in certain Mattermost versions where the system fails to properly validate the relationship between a post being updated and the MSTeams plugin OAuth flow. This flaw allows an attacker to edit arbitrary posts by using a specially crafted MSTeams plugin OAuth redirect URL.

Impact Analysis

An attacker exploiting this vulnerability can modify posts they should not have access to by crafting a malicious OAuth redirect URL. This can lead to unauthorized changes in content, potentially causing misinformation, disruption of communication, or manipulation of data within the Mattermost platform.

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