What’s Vulnerable › Vulnerabilities
CVE-2017-18889
- Severity: medium (CVSS 4.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.7% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2020-06-19 · updated 2026-06-17
- Weakness: CWE-20
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.
Affected products
- Mattermost: before 4.1.2; from 4.2.0 before 4.2.1; 4.3.0-rc1, 4.3.0-rc2, 4.3.0-rc3, 4.3.0-rc4 — fixed in 4.1.2, 4.2.1
How to fix
Upgrade to a fixed version: Mattermost 4.1.2, 4.2.1. Check the vendor advisory for mitigations.
References
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