Authenticated information disclosure via skipped WebSocket MFA
Published Nov 14, 2025 · Updated Nov 14, 2025
Authentication bypass in Mattermost before 11.0.0 allows remote authenticated users to read sensitive data through WebSocket events. The WebConn authorization path treated a valid basic session as fully authenticated and sent or processed events without calling MFARequired for users who had not completed MFA. Exploitation requires valid primary credentials, enforced MFA, and a session that has not completed the second factor; impact is limited to information exposed by reachable events.
Summary
What happened
Authentication bypass in Mattermost before 11.0.0 allows remote authenticated users to read sensitive data through WebSocket events. The WebConn authorization path treated a valid basic session as fully authenticated and sent or processed events without calling MFARequired for users who had not completed MFA. Exploitation requires valid primary credentials, enforced MFA, and a session that has not completed the second factor; impact is limited to information exposed by reachable events.
The record
- CVE
- CVE-2025-55070
- Published
- Nov 14, 2025
- Updated
- Nov 14, 2025
- Vendor
- Mattermost
- Product
- Mattermost
- Classifications
- CWE-306, T1078
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 14, 2025CVE publishedPublication date reported by the CVE source.
- Nov 14, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<11 <=<11
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo