Mattermost Server is vulnerable to webhook and slash command manipulation

GHSA-jp57-4x34-5v94 · CVE-2017-18889 · GO-2025-4201

Published May 24, 2022 · Modified Dec 15, 2025

Description

An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2. An attacker could create fictive system-message posts via webhooks and slash commands, in the v3 or v4 REST API.

References

ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2017-18889
PACKAGE https://github.com/mattermost/mattermost
WEB https://mattermost.com/security-updates

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