CVE-2023-43796

Description

Synapse is an open-source Matrix homeserver Prior to versions 1.95.1 and 1.96.0rc1, cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver. System administrators are encouraged to upgrade to Synapse 1.95.1 or 1.96.0rc1 to receive a patch. As a workaround, the `federation_domain_whitelist` can be used to limit federation traffic with a homeserver.

How to fix CVE-2023-43796

To remediate CVE-2023-43796, upgrade the affected package to a fixed version below.

• —upgrade to 1.95.1-1 or later
• —upgrade to 1.95.1 or later
• —upgrade to daec55e1fe120c564240c5386e77941372bf458f or later

Is CVE-2023-43796 being exploited?

Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.

Affected packages (3)

• from 0, < 1.95.1-1
• from 0, < 1.95.1
• from 0, < daec55e1fe120c564240c5386e77941372bf458f | from 0, < 1.95.1

CVSS scores

References (9)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2023-43796
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2023-43796
• PATCHgithub.com/matrix-org/synapse
• WEBgithub.com/matrix-org/synapse/commit/daec55e1fe120c564240c5386e77941372bf458f