{"id":"CVE-2023-32683","state":"PUBLISHED","title":"URL deny list bypass via oEmbed and image URLs when generating previews in Synapse","description":"Synapse is a Matrix protocol homeserver written in Python with the Twisted framework. A discovered oEmbed or image URL can bypass the `url_preview_url_blacklist` setting potentially allowing server side request forgery or bypassing network policies. Impact is limited to IP addresses allowed by the `url_preview_ip_range_blacklist` setting (by default this only allows public IPs) and by the limited information returned to the client: 1. For discovered oEmbed URLs, any non-JSON response or a JSON response which includes non-oEmbed information is discarded. 2. For discovered image URLs, any non-image response is discarded. Systems which have URL preview disabled (via the `url_preview_enabled` setting) or have not configured a `url_preview_url_blacklist` are not affected. This issue has been addressed in version 1.85.0. Users are advised to upgrade. User unable to upgrade may also disable URL previews.","publishedAt":"2023-06-06T18:24:30.457Z","updatedAt":"2025-02-13T16:54:58.218Z","severity":{"score":3.5,"label":"Low","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["matrix-org synapse"],"affected":[{"vendor":"matrix-org","product":"synapse","versions":[{"version":"< 1.85.0","status":"affected"}]}],"references":["https://github.com/matrix-org/synapse/security/advisories/GHSA-98px-6486-j7qc","https://github.com/matrix-org/synapse/pull/15601","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/X6DH5A5YEB5LRIPP32OUW25FCGZFCZU2/"],"weaknesses":["CWE-863"],"ingestedAt":"2026-10-29T20:06:00.499Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/32xxx/CVE-2023-32683.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2023-32683","state":"PUBLISHED","datePublished":"2023-06-06T18:24:30.457Z","dateUpdated":"2025-02-13T16:54:58.218Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2023-05-11T16:33:45.731Z"},"containers":{"cna":{"title":"URL deny list bypass via oEmbed and image URLs when generating previews in Synapse","descriptions":[{"lang":"en","value":"Synapse is a Matrix protocol homeserver written in Python with the Twisted framework. 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