Headline
CVE-2023-43796: Leak of remote user device information
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.
Package
pip matrix-synapse (pip)
Affected versions
< 1.95.1
Patched versions
1.95.1, 1.96.0rc1
Description
Impact
Cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver.
Patches
System administrators are encouraged to upgrade to Synapse 1.95.1 as soon as possible.
Workarounds
The federation_domain_whitelist can be used to limit federation traffic with a homeserver.
Related news
Gentoo Linux Security Advisory 202401-12 - Multiple vulnerabilities have been found in Synapse, the worst of which could result in information leaks. Versions greater than or equal to 1.96.0 are affected.
### Impact Cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver. ### Patches System administrators are encouraged to upgrade to Synapse 1.95.1 as soon as possible. ### Workarounds The `federation_domain_whitelist` can be used to limit federation traffic with a homeserver.