{"id":"CVE-2023-32683","aliases":["ALPINE-CVE-2023-32683","DEBIAN-CVE-2023-32683","EUVD-2023-0141","GHSA-98px-6486-j7qc","PYSEC-2023-85","UBUNTU-CVE-2023-32683","USN-7444-1","openSUSE-SU-2024:13039-1"],"status":"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.","severity":{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00605,"percentile":0.49236,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-863","CWE-918"],"published":"2023-06-06T16:41:34Z","modified":"2026-11-03T06:32:48Z","fixes":[{"ecosystem":"PyPI","package":"matrix-synapse","fixed_in":["1.85.0"],"sources":["ghsa","osv"]},{"ecosystem":"Alpine:v3.18","package":"synapse","fixed_in":["1.85.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.19","package":"synapse","fixed_in":["1.85.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.20","package":"synapse","fixed_in":["1.85.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.21","package":"synapse","fixed_in":["1.85.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.22","package":"synapse","fixed_in":["1.85.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.23","package":"synapse","fixed_in":["1.85.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"synapse","fixed_in":["1.85.1-r0"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:18.04:LTS","package":"matrix-synapse","fixed_in":["0.24.0+dfsg-1ubuntu0.1~esm4"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:20.04:LTS","package":"matrix-synapse","fixed_in":["1.11.0-1ubuntu0.1~esm2"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:22.04:LTS","package":"matrix-synapse","fixed_in":["1.53.0-1ubuntu0.1~esm2"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.18","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.19","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.20","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.21","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.22","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.23","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.24","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.1-r0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.0"}]}],"versions":["0.33.5","0.33.5.1","0.33.6","0.33.6rc1","0.33.7","0.33.7rc1","0.33.7rc2","0.33.8","0.33.8rc2","0.33.9","0.34.0","0.34.0.1","0.34.0rc1","0.34.0rc2","0.34.1.1","0.99.0","0.99.0rc1","0.99.0rc2","0.99.0rc3","0.99.0rc4","0.99.1","0.99.1.1","0.99.1rc1","0.99.1rc2","0.99.2","0.99.2rc1","0.99.3","0.99.3.1","0.99.3.2","0.99.3rc1","0.99.4","0.99.4rc1","0.99.5","0.99.5.1","0.99.5.2","0.99.5rc1","1.0.0","1.0.0rc1","1.0.0rc2","1.0.0rc3","1.1.0","1.1.0rc1","1.1.0rc2","1.10.0","1.10.0rc1","1.10.0rc2","1.10.0rc3","1.10.0rc5","1.10.1","1.11.0","1.11.0rc1","1.11.1","1.12.0","1.12.0rc1","1.12.1","1.12.1rc1","1.12.2","1.12.3","1.12.4","1.12.4rc1","1.13.0","1.13.0rc1","1.13.0rc2","1.13.0rc3","1.14.0","1.14.0rc1","1.14.0rc2","1.15.0","1.15.0rc1","1.15.1","1.15.2","1.16.0","1.16.0rc1","1.16.0rc2","1.16.1","1.17.0","1.17.0rc1","1.18.0","1.18.0rc1","1.18.0rc2","1.19.0","1.19.0rc1","1.19.1","1.19.1rc1","1.19.2","1.19.3","1.2.0","1.2.0rc1","1.2.0rc2","1.2.1","1.20.0","1.20.0rc1","1.20.0rc2","1.20.0rc3","1.20.0rc4","1.20.0rc5","1.20.1","1.21.0","1.21.0rc1","1.21.0rc2","1.21.0rc3","1.21.1","1.21.2","1.22.0","1.22.0rc1","1.22.0rc2","1.22.1","1.23.0","1.23.0rc1","1.23.1","1.24.0","1.24.0rc1","1.24.0rc2","1.25.0","1.25.0rc1","1.26.0","1.26.0rc1","1.26.0rc2","1.27.0","1.27.0rc1","1.27.0rc2","1.28.0","1.28.0rc1","1.29.0","1.29.0rc1","1.3.0","1.3.0rc1","1.3.1","1.30.0","1.30.0rc1","1.30.1","1.31.0","1.31.0rc1","1.32.0","1.32.0rc1","1.32.1","1.32.2","1.33.0","1.33.0rc1","1.33.0rc2","1.33.1","1.33.2","1.34.0","1.34.0rc1","1.35.0","1.35.0rc1","1.35.0rc2","1.35.0rc3","1.35.1","1.36.0","1.36.0rc1","1.36.0rc2","1.37.0","1.37.0rc1","1.37.1","1.37.1rc1","1.38.0","1.38.0rc1","1.38.0rc2","1.38.0rc3","1.38.1","1.39.0","1.39.0rc1","1.39.0rc2","1.39.0rc3","1.4.0","1.4.0rc1","1.4.0rc2","1.4.1","1.4.1rc1","1.40.0","1.40.0rc1","1.40.0rc2","1.40.0rc3","1.41.0","1.41.0rc1","1.41.1","1.42.0","1.42.0rc1","1.42.0rc2","1.43.0","1.43.0rc1","1.43.0rc2","1.44.0","1.44.0rc1","1.44.0rc2","1.44.0rc3","1.45.0","1.45.0rc1","1.45.0rc2","1.45.1","1.46.0","1.46.0rc1","1.47.0","1.47.0rc1","1.47.0rc2","1.47.0rc3","1.47.1","1.48.0","1.48.0r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rix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.24.0+dfsg-1ubuntu0.1~esm4"}]}],"versions":["0.19.2+dfsg-6","0.24.0+dfsg-1","0.24.0+dfsg-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.11.0-1ubuntu0.1~esm2"}]}],"versions":["1.3.0-1","1.4.0-1","1.5.0-1","1.5.1-1","1.6.0-1","1.6.1-1","1.7.0-2","1.7.1-1","1.7.2-1","1.7.3-1","1.8.0-1","1.9.0-1","1.9.1-1","1.10.0-1","1.10.0-2","1.11.0-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:22.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.53.0-1ubuntu0.1~esm2"}]}],"versions":["1.39.0-1","1.47.0-2","1.47.1-1","1.48.0-1","1.49.0-1","1.49.2-1","1.50.1-1","1.50.2-1","1.51.0-1","1.52.0-1","1.53.0-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.24.0+dfsg-1ubuntu0.1~esm4"}]}],"versions":["0.19.2+dfsg-6","0.24.0+dfsg-1","0.24.0+dfsg-1ubuntu0.1~esm1"],"bundled":8},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.11.0-1ubuntu0.1~esm2"}]}],"versions":["1.3.0-1","1.4.0-1","1.5.0-1","1.5.1-1","1.6.0-1","1.6.1-1","1.7.0-2","1.7.1-1","1.7.2-1","1.7.3-1","1.8.0-1","1.9.0-1","1.9.1-1","1.10.0-1","1.10.0-2","1.11.0-1"],"bundled":8},{"source":"osv","ecosystem":"Ubuntu:Pro:22.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.53.0-1ubuntu0.1~esm2"}]}],"versions":["1.39.0-1","1.47.0-2","1.47.1-1","1.48.0-1","1.49.0-1","1.49.2-1","1.50.1-1","1.50.2-1","1.51.0-1","1.52.0-1","1.53.0-1"],"bundled":8},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.85.2-1.1"}]}],"bundled":2}],"products":[{"vendor":"element-hq","product":"synapse"},{"vendor":"matrix","product":"synapse"},{"vendor":"matrix-org","product":"synapse"}],"references":[{"url":"https://github.com/matrix-org/synapse/security/advisories/GHSA-98px-6486-j7qc","tags":["x_refsource_CONFIRM","x_transferred","Mitigation","Patch","Vendor Advisory","advisory","web","fix","report"]},{"url":"https://github.com/matrix-org/synapse/pull/15601","tags":["x_refsource_MISC","x_transferred","Patch","fix","web","report"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/X6DH5A5YEB5LRIPP32OUW25FCGZFCZU2/","tags":["x_transferred","web"]},{"url":"https://github.com/matrix-org/synapse/releases/tag/v1.85.0","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-32683","tags":["advisory"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2023-85.yaml","tags":["web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/X6DH5A5YEB5LRIPP32OUW25FCGZFCZU2","tags":["web"]},{"url":"https://github.com/advisories/GHSA-98px-6486-j7qc"},{"url":"https://security.alpinelinux.org/vuln/CVE-2023-32683","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/32xxx/CVE-2023-32683.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2023-32683","tags":["advisory"]},{"url":"https://github.com/matrix-org/synapse","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2023-32683","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2023-32683","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-7444-1","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2022-39335","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2022-39374","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2023-41335","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2023-42453","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2023-43796","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2024-31208","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2024-53863","tags":["report"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2023-32682","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-32683","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2023-32683","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.","status":"published","published":"2023-06-06T18:24:30.457Z","modified":"2025-02-13T16:54:58.218Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-863"],"updated_at":"2026-11-02T14:35:29.381004Z"}],"euvd":[{"id":"EUVD-2023-0141","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.","status":"published","published":"2023-06-06T18:24:30Z","modified":"2025-02-13T16:54:58Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"updated_at":"2026-11-03T00:03:50.427692Z"}],"ghsa":[{"id":"GHSA-98px-6486-j7qc","title":"Synapse has URL deny list bypass via oEmbed and image URLs when generating previews","description":"### Impact\nA 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:\n\n* For discovered oEmbed URLs, any non-JSON response or a JSON response which includes non-oEmbed information is discarded.\n* For discovered image URLs, any non-image response is discarded.\n\nSystems which have URL preview disabled (via the `url_preview_enabled` setting) or have not configured a `url_preview_url_blacklist` are not affected.\n\nBecause of the uncommon configuration required, the limited information a malicious user, and the amount of guesses/time the attack would need; the severity is rated as low.\n\n### Patches\n\nThe issue is fixed by #15601.\n\n### Workarounds\n\nThe default configuration of the `url_preview_ip_range_blacklist` should protect against requests being made to internal infrastructure, URL previews of public URLs is expected.\n\nAlternately URL previews could be disabled using the `url_preview_enabled` setting.","status":"published","published":"2023-06-06T16:41:34Z","modified":"2024-09-30T20:34:44Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"},{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-863","CWE-918"],"updated_at":"2026-11-02T14:38:07.852618Z"}],"nvd":[{"id":"CVE-2023-32683","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.","status":"published","published":"2023-06-06T19:15:11.963Z","modified":"2026-06-17T05:59:22.977Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-863","CWE-918"],"updated_at":"2026-11-02T14:08:05.329837Z"}],"osv":[{"id":"ALPINE-CVE-2023-32683","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.","status":"published","published":"2023-06-06T19:15:11.963Z","modified":"2026-11-03T06:32:48.435075292Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-03T07:16:46.202932Z"},{"id":"CVE-2023-32683","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.","status":"published","published":"2023-06-06T18:24:30.457Z","modified":"2026-10-28T02:30:54.432813445Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-863"],"updated_at":"2026-11-02T15:44:32.116263Z"},{"id":"DEBIAN-CVE-2023-32683","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.","status":"withdrawn","published":"2023-06-06T19:15:11.963Z","modified":"2026-08-11T20:49:50.315172829Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:39.679062Z"},{"id":"GHSA-98px-6486-j7qc","title":"Synapse has URL deny list bypass via oEmbed and image URLs when generating previews","description":"### Impact\nA 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:\n\n* For discovered oEmbed URLs, any non-JSON response or a JSON response which includes non-oEmbed information is discarded.\n* For discovered image URLs, any non-image response is discarded.\n\nSystems which have URL preview disabled (via the `url_preview_enabled` setting) or have not configured a `url_preview_url_blacklist` are not affected.\n\nBecause of the uncommon configuration required, the limited information a malicious user, and the amount of guesses/time the attack would need; the severity is rated as low.\n\n### Patches\n\nThe issue is fixed by #15601.\n\n### Workarounds\n\nThe default configuration of the `url_preview_ip_range_blacklist` should protect against requests being made to internal infrastructure, URL previews of public URLs is expected.\n\nAlternately URL previews could be disabled using the `url_preview_enabled` setting.","status":"published","published":"2023-06-06T16:41:34Z","modified":"2024-09-30T20:48:32.953888Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"},{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-863","CWE-918"],"updated_at":"2026-11-02T15:46:43.524801Z"},{"id":"UBUNTU-CVE-2023-32683","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.","status":"published","published":"2023-06-06T19:15:00Z","modified":"2026-02-04T03:29:32.306928Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T16:54:20.997471Z"},{"id":"openSUSE-SU-2024:13039-1","title":"matrix-synapse-1.85.2-1.1 on GA media","description":"These are all security issues fixed in the matrix-synapse-1.85.2-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T03:20:53.96465Z","updated_at":"2026-11-02T16:58:36.025801Z"},{"id":"PYSEC-2023-85","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.","status":"published","published":"2023-06-06T19:15:00Z","modified":"2023-11-08T04:12:35.562423Z","updated_at":"2026-11-02T15:52:53.837392Z"},{"id":"USN-7444-1","title":"matrix-synapse vulnerabilities","description":"It was discovered that Synapse network policies could be bypassed via\nspecially crafted URLs. An attacker could possibly use this issue to\nbypass authentication mechanisms. (CVE-2023-32683)\n\nIt was discovered that Synapse exposed cached device information. An\nattacker could possibly use this issue to gain access to sensitive\ninformation. (CVE-2023-43796)\n\nIt was discovered that Synapse could be tricked into rejecting state\nchanges in rooms. An attacker could possibly use this issue to cause\nSynapse to stop functioning properly, resulting in a denial of service.\nThis issue was only fixed in Ubuntu 20.04 LTS and Ubuntu 22.04 LTS.\n(CVE-2022-39374)\n\nIt was discovered that Synapse stored user credentials in a server's\ndatabase temporarily. An attacker could possibly use this issue to\ngain access to sensitive information. This issue was only fixed in\nUbuntu 22.04 LTS. (CVE-2023-41335)\n\nIt was discovered that Synapse could incorrectly respond to server\nauthorization events. An attacker could possibly use this issue to\nbypass authentication mechanisms. This issue was only fixed in Ubuntu\n22.04 LTS. (CVE-2022-39335)\n\nIt was discovered that Synapse could be manipulated to mark messages\nas read when they had not been viewed. An attacker could possibly use\nthis issue to perform repudiation-based attacks. This issue was only\nfixed in Ubuntu 22.04 LTS. (CVE-2023-42453)\n\nIt was discovered that Synapse had several memory-related issues. An\nattacker could possibly use this issue to cause Synapse to crash,\nresulting in a denial of service. This issue was only fixed in Ubuntu\n22.04 LTS. (CVE-2024-31208)\n\nIt was discovered that Synapse could run external tools due to a\nunchecked thumbnail rendering routine. An attacker could possibly use\nthis issue to cause Synapse to crash, resulting in a denial of service,\nor execute arbitrary code. This issue was only fixed in Ubuntu\n22.04 LTS. (CVE-2024-53863)\n","status":"published","published":"2025-04-22T17:24:26Z","modified":"2026-04-27T18:02:27.885669037Z","updated_at":"2026-11-02T16:58:19.988474Z"}]}}