CVE-2021-29433

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.

• CWE-20
• CWE-400

• https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1daPatch, Third Party Advisory
• https://github.com/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553Patch, Third Party Advisory
• https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1daPatch, Third Party Advisory
• https://github.com/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553Patch, Third Party Advisory

Published

Apr 15, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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