CVE-2023-50333 : Security Advisory and Response

Mattermost fails to update the permissions of the current session for a user who was just demoted to guest, allowing freshly demoted guests to change group names.

Understanding CVE-2023-50333

This CVE-2023-50333 vulnerability in Mattermost can potentially allow freshly demoted guests to change group names due to a lack of restriction in managing group names.

What is CVE-2023-50333?

CVE-2023-50333 highlights a security issue in Mattermost where permissions are not properly updated for users who were demoted to guests, resulting in a risk scenario where guests can tamper with group names.

The Impact of CVE-2023-50333

The impact of this vulnerability lies in the fact that freshly demoted users are able to manipulate group names within the platform, potentially leading to confusion, unauthorized access, or malicious activities.

Technical Details of CVE-2023-50333

The vulnerability is classified under CWE-284: Improper Access Control with a CVSS v3.1 base score of 3.7 (Low severity). It has a high attack complexity, requires network access, and low privileges required, with user interaction being necessary for exploitation.

Vulnerability Description

Mattermost fails to update permissions for users demoted to guests, enabling these users to change group names, posing a security risk within the platform.

Affected Systems and Versions

The vulnerability affects Mattermost versions 9.2.2 and below, as well as version 8.1.6. Version 8.1.7 is unaffected by this issue.

Exploitation Mechanism

Exploitation of this vulnerability requires a demotion of user privileges to guest status, enabling unauthorized users to modify group names.

Mitigation and Prevention

To address CVE-2023-50333, immediate steps should be taken to mitigate the risk and prevent unauthorized access or data manipulation.

Immediate Steps to Take

Update Mattermost Server to versions 8.1.7, 9.3.0, or higher to patch the vulnerability and prevent freshly demoted guests from unauthorized changes.

Long-Term Security Practices

Ensure proper access control mechanisms are in place to prevent unauthorized actions and regularly update systems to address known vulnerabilities.

Patching and Updates

Keep Mattermost Server up to date with the latest security patches and software updates to ensure the platform's security integrity.