CVE-2023-43796 Synapse vulnerable to leak of remote user device information

What is CVE-2023-43796?

CVE-2023-43796 is a medium-severity vulnerability in Fedoraproject Fedora, published on 31 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-200

Which versions are affected by CVE-2023-43796?

3 open source packages ship an affected version, including matrix-synapse. It affects 2 products.

Products include Fedoraproject Fedora, Matrix Synapse.

How do I fix CVE-2023-43796?

Upgrade matrix-synapse to 1.95.1 or later.

Is CVE-2023-43796 being exploited?

There is no known exploitation of CVE-2023-43796 in the wild and no public exploit code.

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• CVE-2024-4947 Google Chromium V8 Type Confusion Exploited Critical 9.6
• CVE-2024-4671 Google Chromium Visuals Use-After-Free Exploited Critical 9.6

All Fedoraproject Fedora vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-mp92-3jfm-3575, PYSEC-2023-230, UBUNTU-CVE-2023-43796, openSUSE-SU-2024:13392-1.