CVE-2026-22880
Mattermost Mobile Apps SSO Authentication Origin Validation Flaw
Publication date: 2026-05-21
Last updated on: 2026-05-21
Assigner: Mattermost, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mattermost | mobile_apps | to 2.37 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-352 | The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability affects Mattermost Mobile Apps versions up to 2.37, 11.4, 2.0.37, 11.0.4, 11.1.3, 11.3.2, and 10.11.11.0. The issue is that these versions fail to properly validate the Single Sign-On (SSO) authentication callback origin.
Because of this improper validation, an attacker who controls a malicious Mattermost server can steal user credentials for a legitimate Mattermost server. This is done by relaying the SSO code exchange flow through the mobile application.
How can this vulnerability impact me? :
The vulnerability allows an attacker to steal user credentials for a legitimate Mattermost server by exploiting the mobile app's failure to validate the SSO authentication callback origin.
This can lead to unauthorized access to user accounts, potentially compromising sensitive information and communications within the Mattermost environment.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should update your Mattermost Mobile Apps to a version later than those affected (versions > 2.37, 11.4, 2.0.37, 11.0.4, 11.1.3, 11.3.2, 10.11.11.0) as the issue involves improper validation of the SSO authentication callback origin.
Additionally, stay informed about security updates and patches by regularly checking the Mattermost Security Updates page and subscribing to their Security Bulletin for fix release notifications.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability allows an attacker controlling a malicious Mattermost server to steal user credentials for a legitimate Mattermost server by exploiting improper validation of the SSO authentication callback origin. This credential theft could lead to unauthorized access to user data.
Such unauthorized access and potential exposure of user credentials may impact compliance with data protection standards and regulations like GDPR and HIPAA, which require safeguarding user authentication data and preventing unauthorized access.
However, the provided information does not explicitly detail the direct compliance implications or specific regulatory impacts of this vulnerability.