{"id":"CVE-2023-43796","aliases":["GHSA-mp92-3jfm-3575","PYSEC-2023-230"],"title":"Synapse vulnerable to leak of remote user device information","summary":"Synapse vulnerable to leak of remote user device information","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","vendor":"matrix-synapse","product":"matrix-synapse","ecosystem":"pip","affected":["matrix-synapse < 1.95.1"],"patched":["matrix-synapse 1.95.1"],"published":"2023-10-31","updated":"2026-09-10","sourceUpdated":"2026-09-10T03:49:24.728166201Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-mp92-3jfm-3575","references":[{"url":"https://github.com/matrix-org/synapse/security/advisories/GHSA-mp92-3jfm-3575"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-43796"},{"url":"https://github.com/matrix-org/synapse/commit/daec55e1fe120c564240c5386e77941372bf458f"},{"url":"https://github.com/matrix-org/synapse"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2023-230.yaml"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2IDEEZMFJBDLTFHQUTZRJJNCOZGQ2ZVS"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VH3RNC5ZPQZ4OKPSL4E6BBJSZOQLGDEY"},{"url":"https://security.gentoo.org/glsa/202401-12"}],"tags":["osv","pip"],"epss":0.00897,"epssPercentile":0.58067,"ingestedAt":"2026-09-12T03:13:01.711Z","slug":"CVE-2023-43796","body":"## Overview\n\n### Impact\nCached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver.\n\n### Patches\nSystem administrators are encouraged to upgrade to Synapse 1.95.1 as soon as possible.\n\n### Workarounds\nThe `federation_domain_whitelist` can be used to limit federation traffic with a homeserver.\n\n## Affected packages\n\n- `matrix-synapse < 1.95.1`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `matrix-synapse 1.95.1`","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[]}