CVE-2017-18889: Input Validation

Published Jun 19, 2020
·
Updated

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 Software

6 affected components
Mattermost Mattermost Server<4.1.2
Mattermost Mattermost Server>=4.2.0<4.2.1
Mattermost Mattermost Server=4.3.0-rc1
Mattermost Mattermost Server=4.3.0-rc2
Mattermost Mattermost Server=4.3.0-rc3
Mattermost Mattermost Server=4.3.0-rc4

Event History

Jun 19, 2020
CVE Published
via MITRE·06:08 PM
Data Sourced
via MITRE·06:08 PM
Description

Frequently Asked Questions

1

What is the severity of CVE-2017-18889?

CVE-2017-18889 has a medium severity rating, as it allows an attacker to post fictive system messages.

2

How do I fix CVE-2017-18889?

To mitigate CVE-2017-18889, update Mattermost Server to version 4.3.0 or higher.

3

What systems are affected by CVE-2017-18889?

CVE-2017-18889 affects Mattermost Server versions below 4.3.0, 4.2.1, and 4.1.2.

4

What types of attacks are possible with CVE-2017-18889?

With CVE-2017-18889, attackers can exploit webhooks and slash commands to create misleading system message posts.

5

Are there any workarounds for CVE-2017-18889?

There are no official workarounds for CVE-2017-18889; updating to a patched version is the only solution.

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203