CVE-2019-20883 : Security Advisory and Response

A problem has been detected in versions prior to 5.8.0 of Mattermost Server, where the ability to set Town Square as Read-Only does not prevent users from pinning or unpinning a post.

Understanding CVE-2019-20883

An issue was discovered in Mattermost Server before 5.8.0, when Town Square is set to Read-Only. Users can pin or unpin a post.

What is CVE-2019-20883?

CVE-2019-20883 is a vulnerability in Mattermost Server versions prior to 5.8.0 that allows users to pin or unpin posts despite the Town Square being set as Read-Only.

The Impact of CVE-2019-20883

This vulnerability could lead to unauthorized users manipulating pinned posts in a Read-Only Town Square setting, potentially compromising the integrity of the communication platform.

Technical Details of CVE-2019-20883

Mattermost Server versions before 5.8.0 are affected by this vulnerability.

Vulnerability Description

The issue arises when users are able to pin or unpin posts in a Read-Only Town Square, contrary to the intended restriction.

Affected Systems and Versions

Product: Mattermost Server
Versions Affected: Prior to 5.8.0

Exploitation Mechanism

Unauthorized users can exploit this vulnerability by pinning or unpinning posts in a Read-Only Town Square, bypassing the intended restrictions.

Mitigation and Prevention

It is crucial to take immediate steps to address and prevent the exploitation of CVE-2019-20883.

Immediate Steps to Take

Upgrade Mattermost Server to version 5.8.0 or later to mitigate the vulnerability.
Monitor and restrict user permissions to prevent unauthorized actions.

Long-Term Security Practices

Regularly update and patch Mattermost Server to ensure the latest security fixes are in place.
Conduct security audits and assessments to identify and address any potential vulnerabilities.

Patching and Updates

Apply patches and updates provided by Mattermost promptly to address security vulnerabilities and enhance system security.