{"id":"CVE-2021-29433","aliases":["GHSA-pw4v-gr34-2553","PYSEC-2021-24"],"title":"Sydent DoS (via resource exhaustion) due to improper input validation","summary":"Sydent DoS (via resource exhaustion) due to improper input validation","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","vendor":"matrix-sydent","product":"matrix-sydent","ecosystem":"pip","affected":["matrix-sydent < 2.3.0"],"patched":["matrix-sydent 2.3.0"],"published":"2021-04-16","updated":"2026-09-10","sourceUpdated":"2026-09-10T03:49:03.750308427Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-pw4v-gr34-2553","references":[{"url":"https://github.com/matrix-org/sydent/security/advisories/GHSA-pw4v-gr34-2553"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29433"},{"url":"https://github.com/matrix-org/sydent/commit/3175fd358ebc2c310eab7a3dbf296ce2bd54c1da"},{"url":"https://github.com/matrix-org/sydent"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-24.yaml"},{"url":"https://pypi.org/project/matrix-sydent"}],"tags":["osv","pip"],"epss":0.00927,"epssPercentile":0.58989,"ingestedAt":"2026-09-12T03:13:01.718Z","slug":"CVE-2021-29433","body":"## Overview\n\n### 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.\n\n## Affected packages\n\n- `matrix-sydent < 2.3.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `matrix-sydent 2.3.0`","depth":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[]}