{"id":"CVE-2021-29433","aliases":["GHSA-pw4v-gr34-2553","PYSEC-2021-24"],"url":"https://o3.security/vulnerability/CVE-2021-29433","summary":"Sydent DoS (via resource exhaustion) due to improper input validation","details":"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.","published":"2021-04-15T18:15:12.497Z","modified":"2026-07-09T01:26:02.872714Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"matrix-sydent","fixedVersion":"2.3.0"}],"fix":{"url":"https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1da","label":"matrix-org/sydent@3175fd3"},"references":[{"type":"FIX","url":"https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1da"},{"type":"FIX","url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T01:26:02.872714Z"}}