WebSocket Vulnerability in Mattermost by Mattermost Inc.
CVE-2025-55070

6.5MEDIUM

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
14 November 2025

What is CVE-2025-55070?

A significant vulnerability exists in Mattermost versions prior to 11, where the multi-factor authentication mechanism is not enforced on WebSocket connections. This oversight allows unauthenticated users to gain access to sensitive information through WebSocket events, posing a considerable security risk. It is crucial for users to upgrade to the latest version to mitigate this vulnerability and protect their data.

Affected Version(s)

Mattermost <11 <= 11

Mattermost 11.0.0

References

https://mattermost.com/security-updates

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Agniva De Sarker
JSON
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CVE-2025-55070 : WebSocket Vulnerability in Mattermost by Mattermost Inc.