CVE-2022-39200 : What You Need to Know

Dendrite, a Matrix homeserver developed by Matrix.org, was found to have a vulnerability where signatures were not properly verified for events retrieved from a remote homeserver via the

/get_missing_events

path. This issue could potentially lead to the acceptance of invalid or modified events by Dendrite.

Understanding CVE-2022-39200

This section delves into the details of the CVE-2022-39200 vulnerability.

What is CVE-2022-39200?

CVE-2022-39200 is a vulnerability in Dendrite, a Matrix homeserver written in Go. It arises from missing signature checks for events retrieved from a remote homeserver using the

/get_missing_events

path.

The Impact of CVE-2022-39200

The impact of CVE-2022-39200 is rated as HIGH with a base score of 7.3. The vulnerability could potentially allow a remote homeserver to supply invalid or modified events to Dendrite, compromising its integrity.

Technical Details of CVE-2022-39200

This section covers the technical aspects of the CVE-2022-39200 vulnerability.

Vulnerability Description

In affected versions of Dendrite (versions prior to 0.9.8), signatures for events retrieved via the

/get_missing_events

path were not properly verified. This allowed remote homeservers to send potentially malicious events to Dendrite.

Affected Systems and Versions

The vulnerability affects Dendrite versions earlier than 0.9.8.

Exploitation Mechanism

The exploitation occurs when a remote homeserver sends invalid or modified events to Dendrite via the

/get_missing_events

path due to the lack of signature verification.

Mitigation and Prevention

To address CVE-2022-39200, follow the mitigation and prevention measures outlined below.

Immediate Steps to Take

Users are strongly advised to upgrade to Dendrite version 0.9.8 or later to mitigate the vulnerability. Ensure timely patching to maintain system security.

Long-Term Security Practices

Incorporate regular security audits and testing to identify and address vulnerabilities promptly. Follow security best practices to safeguard against similar issues.

Patching and Updates

Keep Dendrite updated with the latest security patches and versions to stay protected against known vulnerabilities.