CVE-2025-12689: DoS in Calls plugin via malformed UTF-8 in WebSocket request

Published Dec 17, 2025
·
Updated

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.

Affected Software

5 affected componentsFixes available
Mattermost Mattermost<=11.0.4, <=10.12.2, <=10.11.6
go/github.com/mattermost/mattermost-plugin-calls<1.11.0
1.11.0
Mattermost Mattermost Server>=10.11.0<10.11.7
Mattermost Mattermost Server>=10.12.0<10.12.3
Mattermost Mattermost Server>=11.0.0<11.0.5

Remediation

Information

Update Mattermost to versions 11.1.0, 11.0.5, 10.12.3, 10.11.7 or higher.

Event History

Dec 17, 2025
CVE Published
via MITRE·06:14 PM
Data Sourced
via MITRE·06:14 PM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·07:16 PM
DescriptionSeverityWeaknessAffected Software
Advisory Published
via GitHub·09:30 PM
Data Sourced
via GitHub·09:30 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2025-12689?

CVE-2025-12689 has been rated as a medium severity vulnerability due to its potential to crash the Calls plug-in.

2

How do I fix CVE-2025-12689?

To fix CVE-2025-12689, upgrade Mattermost to version 11.0.5 or later, 10.12.3 or later, or 10.11.7 or later.

3

What versions are affected by CVE-2025-12689?

CVE-2025-12689 affects Mattermost versions 11.0.x up to 11.0.4, 10.12.x up to 10.12.2, and 10.11.x up to 10.11.6.

4

What kind of attack does CVE-2025-12689 enable?

CVE-2025-12689 allows attackers to crash the Calls plug-in by sending malformed WebSocket request fields.

5

Where can I find more information on CVE-2025-12689?

For more information on CVE-2025-12689, refer to the security updates section of the Mattermost website.

Contact

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Fortitude Valley,
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info@secalerts.co
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