{"id":"CVE-2021-29433","aliases":["EUVD-2021-0122","GHSA-pw4v-gr34-2553","PYSEC-2021-24"],"status":"published","title":"Denial of service (via resource exhaustion) due to improper input validation","description":"Sydent is a reference Matrix identity server. In Sydent versions 2.2.0 and prior, sissing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion. A patch for the vulnerability is in version 2.3.0. No workarounds are known to exist.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00927,"percentile":0.60799,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-20","CWE-400"],"published":"2021-04-15T17:55:11Z","modified":"2026-10-20T10:54:36Z","fixes":[{"ecosystem":"PyPI","package":"matrix-sydent","fixed_in":["2.3.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"matrix-sydent","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"matrix-sydent","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.0"}]}],"versions":["2.0.0","2.0.1","2.1.0","2.2.0"]},{"source":"osv","ecosystem":"PyPI","package":"matrix-sydent","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.0"}]}],"versions":["2.0.0","2.0.1","2.1.0","2.2.0"]}],"products":[{"vendor":"matrix","product":"sydent"},{"vendor":"matrix-org","product":"sydent"}],"references":[{"url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553","tags":["x_refsource_CONFIRM","x_transferred","Patch","Third Party Advisory","fix","web","advisory"]},{"url":"https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1da","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29433","tags":["advisory"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-24.yaml","tags":["web"]},{"url":"https://pypi.org/project/matrix-sydent","tags":["web"]},{"url":"https://github.com/advisories/GHSA-pw4v-gr34-2553"},{"url":"https://github.com/matrix-org/sydent","tags":["package"]},{"url":"https://pypi.org/project/matrix-sydent/","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2021-29433","title":"Denial of service (via resource exhaustion) due to improper input validation","description":"Sydent is a reference Matrix identity server. In Sydent versions 2.2.0 and prior, sissing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion. A patch for the vulnerability is in version 2.3.0. No workarounds are known to exist.","status":"published","published":"2021-04-15T17:55:11Z","modified":"2024-08-03T22:02:51.915Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:33:06.658806Z"}],"euvd":[{"id":"EUVD-2021-0122","description":"Sydent is a reference Matrix identity server. In Sydent versions 2.2.0 and prior, sissing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion. A patch for the vulnerability is in version 2.3.0. No workarounds are known to exist.","status":"published","published":"2021-04-15T17:55:11Z","modified":"2024-08-03T22:02:51Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-03T03:24:45.541615Z"}],"ghsa":[{"id":"GHSA-pw4v-gr34-2553","title":"Sydent DoS (via resource exhaustion) due to improper input validation","description":"### Impact\n\nMissing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion.\n\n### Patches\n\nFixed by 3175fd3.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at security@matrix.org.","status":"published","published":"2021-04-16T19:53:37Z","modified":"2024-09-24T15:42:43Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium"},{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-20","CWE-400"],"updated_at":"2026-11-02T14:38:05.526697Z"}],"nvd":[{"id":"CVE-2021-29433","description":"Sydent is a reference Matrix identity server. In Sydent versions 2.2.0 and prior, sissing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion. A patch for the vulnerability is in version 2.3.0. No workarounds are known to exist.","status":"published","published":"2021-04-15T18:15:12.497Z","modified":"2026-06-17T03:47:37.947Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium","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:N/A:L","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-20","CWE-400"],"updated_at":"2026-11-02T14:06:52.03307Z"}],"osv":[{"id":"CVE-2021-29433","description":"Sydent is a reference Matrix identity server. In Sydent versions 2.2.0 and prior, sissing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion. A patch for the vulnerability is in version 2.3.0. No workarounds are known to exist.","status":"published","published":"2021-04-15T18:15:12.497Z","modified":"2026-10-20T10:54:36.905414984Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:44:19.129331Z"},{"id":"GHSA-pw4v-gr34-2553","title":"Sydent DoS (via resource exhaustion) due to improper input validation","description":"### Impact\n\nMissing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion.\n\n### Patches\n\nFixed by 3175fd3.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at security@matrix.org.","status":"published","published":"2021-04-16T19:53:37Z","modified":"2026-09-10T03:49:03.750308427Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium"},{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-20","CWE-400"],"updated_at":"2026-11-02T15:46:53.700556Z"},{"id":"PYSEC-2021-24","description":"### Impact Missing input validation of some parameters on the endpoints used to confirm third-party identifiers could cause excessive use of disk space and memory leading to resource exhaustion. ### Patches Fixed by 3175fd3. ### Workarounds There are no known workarounds. ### References n/a ### For more information If you have any questions or comments about this advisory, email us at security@matrix.org.","status":"published","published":"2021-04-15T18:15:00Z","modified":"2023-11-08T04:05:33.83517Z","updated_at":"2026-11-02T15:52:52.682031Z"}]}}