CVE-2022-39200: Signature checks not applied to some retrieved missing events
Dendrite is a Matrix homeserver written in Go. In affected versions events retrieved from a remote homeserver using the /getmissingevents path did not have their signatures verified correctly. This could potentially allow a remote homeserver to provide invalid/modified events to Dendrite via this endpoint. Note that this does not apply to events retrieved through other endpoints (e.g. /event, /state) as they have been correctly verified. Homeservers that have federation disabled are not vulnerable. The problem has been fixed in Dendrite 0.9.8. Users are advised to upgrade. There are no known workarounds for this issue.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is CVE-2022-39200?
CVE-2022-39200 is a vulnerability in the Matrix homeserver Dendrite that allows a remote homeserver to provide invalid/modified events via the `/get_missing_events` path.
What is the severity of CVE-2022-39200?
The severity of CVE-2022-39200 is high with a CVSS score of 5.3.
How can this vulnerability affect me?
This vulnerability can potentially allow a remote homeserver to provide invalid/modified events to your Dendrite Matrix homeserver.
Which versions of Dendrite are affected by CVE-2022-39200?
Versions up to exclusive of 0.9.8 of Dendrite are affected by CVE-2022-39200.
How do I fix CVE-2022-39200?
To fix CVE-2022-39200, update your Dendrite Matrix homeserver to a version higher than 0.9.8.