CVE-2021-29433

CVE-2021-29433 is a resource exhaustion vulnerability affecting Sydent versions 2.2.0 and prior, a reference Matrix identity server. The flaw stems from insufficient input validation on endpoints used to confirm third-party identifiers, leading to excessive disk space and memory consumption. Rated Medium (CVSS 4.3), this vulnerability can be exploited remotely with low attack complexity by a low-privileged attacker, resulting in a denial of service. There is currently no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.