{"cve":"CVE-2023-43796","nvd":{"published":"2023-10-31T17:15:23.270","modified":"2026-06-17T06:26:27.760","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","score":5.3},"cwes":["CWE-200"],"references":["https://github.com/matrix-org/synapse/commit/daec55e1fe120c564240c5386e77941372bf458f","https://github.com/matrix-org/synapse/security/advisories/GHSA-mp92-3jfm-3575","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2IDEEZMFJBDLTFHQUTZRJJNCOZGQ2ZVS/","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VH3RNC5ZPQZ4OKPSL4E6BBJSZOQLGDEY/","https://security.gentoo.org/glsa/202401-12"],"products":["fedoraproject:fedora","matrix:synapse"],"source":"nvd","synced_at":"2026-10-19T21:40:11.519948003+00:00"},"epss":{"cve":"CVE-2023-43796","score":0.00897,"percentile":0.59597,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-mp92-3jfm-3575","url":"https://osv.dev/vulnerability/GHSA-mp92-3jfm-3575","summary":"Synapse vulnerable to leak of remote user device information","modified":"2026-09-10T03:49:24.728166201Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<1.95.1"],"fixed":["1.95.1"]}]},{"id":"PYSEC-2023-230","url":"https://osv.dev/vulnerability/PYSEC-2023-230","summary":"","modified":"2023-11-08T20:56:32.030692Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<1.95.1"],"fixed":["1.95.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}