{"id":"CVE-2023-42453","aliases":["ALPINE-CVE-2023-42453","DEBIAN-CVE-2023-42453","EUVD-2023-0133","GHSA-7565-cq32-vx2x","PYSEC-2023-180","UBUNTU-CVE-2023-42453","USN-7444-1","openSUSE-SU-2024:13270-1"],"status":"published","title":"Improper validation of receipts allows forged read receipts in matrix synapse","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","severity":{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00777,"percentile":0.56079,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-285"],"published":"2023-09-26T19:20:38Z","modified":"2026-11-03T06:32:43Z","fixes":[{"ecosystem":"PyPI","package":"matrix-synapse","fixed_in":["1.93.0"],"sources":["ghsa","osv"]},{"ecosystem":"Alpine:v3.18","package":"synapse","fixed_in":["1.93.0-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.19","package":"synapse","fixed_in":["1.93.0-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.20","package":"synapse","fixed_in":["1.93.0-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.21","package":"synapse","fixed_in":["1.93.0-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.22","package":"synapse","fixed_in":["1.93.0-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.23","package":"synapse","fixed_in":["1.93.0-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"synapse","fixed_in":["1.93.0-r0"],"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":"0.34.0"},{"fixed":"1.93.0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.18","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.34.0"},{"fixed":"1.93.0-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.19","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.34.0"},{"fixed":"1.93.0-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.20","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.34.0"},{"fixed":"1.93.0-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.21","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.34.0"},{"fixed":"1.93.0-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.22","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.34.0"},{"fixed":"1.93.0-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.23","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.34.0"},{"fixed":"1.93.0-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.24","package":"synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.34.0"},{"fixed":"1.93.0-r0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.34.0"},{"fixed":"1.93.0"}]}],"versions":["0.34.0","0.34.0.1","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","1.48.0rc1","1.49.0","1.49.0rc1","1.49.2","1.5.0","1.5.0rc1","1.5.0rc2","1.5.1","1.50.0","1.50.0rc1","1.50.0rc2","1.50.1","1.50.2","1.51.0","1.51.0rc1","1.51.0rc2","1.52.0","1.52.0rc1","1.53.0","1.53.0rc1","1.54.0","1.54.0rc1","1.55.0","1.55.0rc1","1.55.1","1.55.2","1.56.0","1.56.0rc1","1.57.0","1.57.0rc1","1.57.1","1.58.0","1.58.0rc2","1.58.1","1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Advisory","advisory","web","report"]},{"url":"https://github.com/matrix-org/synapse/pull/16327","tags":["x_refsource_MISC","x_transferred","Issue Tracking","Patch","fix","web","report"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/65QPC55I4D27HIZP7H2NQ34EOXHPP4AO/","tags":["x_transferred","Mailing List","Release Notes","web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2AFB2Y3S2VCPCN5P2XCZTG24MBMZ7DM4/","tags":["x_transferred","Mailing List","Release Notes","web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/N6P4QULVUE254WI7XF2LWWOGHCYVFXFY/","tags":["x_transferred","web"]},{"url":"https://security.gentoo.org/glsa/202401-12","tags":["x_transferred","advisory","web"]},{"url":"https://github.com/matrix-org/synapse/commit/63d28a88c1d18c64ea7e23b6dd7483e6d5dcf881","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-42453","tags":["advisory"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2023-180.yaml","tags":["web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2AFB2Y3S2VCPCN5P2XCZTG24MBMZ7DM4","tags":["web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/65QPC55I4D27HIZP7H2NQ34EOXHPP4AO","tags":["web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/N6P4QULVUE254WI7XF2LWWOGHCYVFXFY","tags":["web"]},{"url":"https://github.com/advisories/GHSA-7565-cq32-vx2x"},{"url":"https://security.alpinelinux.org/vuln/CVE-2023-42453","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/42xxx/CVE-2023-42453.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2023-42453","tags":["advisory"]},{"url":"https://github.com/matrix-org/synapse","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2023-42453","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2023-42453","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-2023-32683","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2023-41335","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-2023-41335","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-42453","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2023-4863","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2023-42453","title":"Improper validation of receipts allows forged read receipts in matrix synapse","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","status":"published","published":"2023-09-26T20:49:23.365Z","modified":"2025-06-18T14:11:32.728Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T14:35:18.16233Z"}],"euvd":[{"id":"EUVD-2023-0133","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","status":"published","published":"2023-09-26T20:49:23Z","modified":"2025-06-18T14:11:32Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"low"}],"updated_at":"2026-11-02T20:32:20.01453Z"}],"ghsa":[{"id":"GHSA-7565-cq32-vx2x","title":"matrix-synapse vulnerable to improper validation of receipts allows forged read receipts","description":"### Impact\nUsers were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room.\n\n### Patches\nhttps://github.com/matrix-org/synapse/pull/16327\n\n### Workarounds\nThere is no workaround.\n","status":"published","published":"2023-09-26T19:20:38Z","modified":"2024-09-24T17:50:31Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"},{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T14:38:05.526697Z"}],"nvd":[{"id":"CVE-2023-42453","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","status":"published","published":"2023-09-27T15:19:32.453Z","modified":"2026-06-17T06:23:51.78Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T14:08:31.699785Z"}],"osv":[{"id":"ALPINE-CVE-2023-42453","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","status":"published","published":"2023-09-27T15:19:32.453Z","modified":"2026-11-03T06:32:43.417268845Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-03T07:17:02.90744Z"},{"id":"CVE-2023-42453","title":"Improper validation of receipts allows forged read receipts in matrix synapse","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","status":"published","published":"2023-09-26T20:49:23.365Z","modified":"2026-10-28T02:31:03.802646117Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T15:44:33.792101Z"},{"id":"DEBIAN-CVE-2023-42453","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","status":"withdrawn","published":"2023-09-27T15:19:32.453Z","modified":"2026-08-11T20:49:51.163476796Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:40.275853Z"},{"id":"GHSA-7565-cq32-vx2x","title":"matrix-synapse vulnerable to improper validation of receipts allows forged read receipts","description":"### Impact\nUsers were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room.\n\n### Patches\nhttps://github.com/matrix-org/synapse/pull/16327\n\n### Workarounds\nThere is no workaround.\n","status":"published","published":"2023-09-26T19:20:38Z","modified":"2026-09-10T03:49:57.892935878Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"low"},{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-285"],"updated_at":"2026-11-02T15:46:40.657155Z"},{"id":"PYSEC-2023-180","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","status":"published","published":"2023-09-27T15:19:00Z","modified":"2023-11-08T04:13:28.660154Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:52:53.837392Z"},{"id":"UBUNTU-CVE-2023-42453","description":"Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.","status":"published","published":"2023-09-27T15:19:00Z","modified":"2026-02-04T03:37:22.725826Z","cvss":[{"version":"3.1","score":3.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"low"},{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T16:54:22.741943Z"},{"id":"openSUSE-SU-2024:13270-1","title":"matrix-synapse-1.93.0-1.1 on GA media","description":"These are all security issues fixed in the matrix-synapse-1.93.0-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T02:24:22.061902Z","updated_at":"2026-11-02T16:58:36.025801Z"},{"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"}]}}