CVE-2019-16738 : Security Advisory and Response

MediaWiki through version 1.33.0 is vulnerable to an information disclosure flaw in Special:Redirect, potentially exposing hidden usernames through a User ID Lookup feature.

Understanding CVE-2019-16738

This CVE identifies a security vulnerability in MediaWiki versions up to 1.33.0 that can lead to the exposure of suppressed usernames.

What is CVE-2019-16738?

In MediaWiki through 1.33.0, the Special:Redirect feature allows for the disclosure of hidden usernames through a User ID Lookup mechanism.

The Impact of CVE-2019-16738

The vulnerability in Special:Redirect can result in the exposure of usernames that are meant to be hidden, compromising user privacy and potentially leading to targeted attacks.

Technical Details of CVE-2019-16738

MediaWiki's Special:Redirect feature is at the core of this vulnerability, allowing for the unintended disclosure of suppressed usernames.

Vulnerability Description

The flaw in Special:Redirect permits the retrieval of hidden usernames through a User ID Lookup, breaching the intended privacy measures.

Affected Systems and Versions

MediaWiki versions up to 1.33.0 are impacted by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by leveraging the User ID Lookup feature in Special:Redirect to reveal usernames that should remain hidden.

Mitigation and Prevention

To address CVE-2019-16738 and enhance overall security, consider the following steps:

Immediate Steps to Take

Upgrade MediaWiki to a version beyond 1.33.0 to mitigate the vulnerability.
Monitor user access and activities to detect any unauthorized attempts to exploit the User ID Lookup feature.

Long-Term Security Practices

Regularly review and update access control policies to ensure sensitive information remains protected.
Conduct security audits to identify and address any potential privacy leaks or data exposure risks.

Patching and Updates

Stay informed about security advisories and updates from MediaWiki to promptly apply patches that address known vulnerabilities.