{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-04-20T21:35:36.681","vulnerabilities":[{"cve":{"id":"CVE-2021-29471","sourceIdentifier":"security-advisories@github.com","published":"2021-05-11T15:15:08.507","lastModified":"2024-11-21T06:01:11.337","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.33.2 \"Push rules\" can specify conditions under which they will match, including `event_match`, which matches event content against a pattern including wildcards. Certain patterns can cause very poor performance in the matching engine, leading to a denial-of-service when processing moderate length events. The issue is patched in version 1.33.2. A potential workaround might be to prevent users from making custom push rules, by blocking such requests at a reverse-proxy."},{"lang":"es","value":"Synapse es un servidor doméstico de referencia de Matrix escrito en python (paquete pypi matrix-synapse). Matrix es un ecosistema para VoIP y mensajería instantánea federada abierta. En Synapse versiones anteriores a 1.33.2, unas \"Push rules\" pueden especificar condiciones bajo las cuales coincidirán, incluyendo \"event_match\", que compara el contenido del evento con un patrón que incluye comodines. Determinados patrones pueden causar un rendimiento muy deficiente en el motor de coincidencia, conllevando a una denegación de servicio cuando se procesan eventos de duración moderada. El problema está parcheado en versión 1.33.2. Una posible solución alternativa podría ser impedir a unos usuarios crear reglas de inserción personalizadas, al bloquear dichas peticiones en un proxy inverso"}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","baseScore":3.7,"baseSeverity":"LOW","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW"},"exploitabilityScore":2.2,"impactScore":1.4},{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW"},"exploitabilityScore":3.9,"impactScore":1.4}],"cvssMetricV2":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"2.0","vectorString":"AV:N/AC:L/Au:N/C:N/I:N/A:P","baseScore":5.0,"accessVector":"NETWORK","accessComplexity":"LOW","authentication":"NONE","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"PARTIAL"},"baseSeverity":"MEDIUM","exploitabilityScore":10.0,"impactScore":2.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-400"}]},{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"CWE-331"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*","versionEndExcluding":"1.33.2","matchCriteriaId":"CA3C30EA-7826-48F6-9367-5632BE392B50"}]}]},{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*","matchCriteriaId":"A930E247-0B43-43CB-98FF-6CE7B8189835"}]}]}],"references":[{"url":"https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c","source":"security-advisories@github.com","tags":["Patch","Third Party Advisory"]},{"url":"https://github.com/matrix-org/synapse/releases/tag/v1.33.2","source":"security-advisories@github.com","tags":["Release Notes","Third Party Advisory"]},{"url":"https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85","source":"security-advisories@github.com","tags":["Patch","Third Party Advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/","source":"security-advisories@github.com"},{"url":"https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch","Third Party Advisory"]},{"url":"https://github.com/matrix-org/synapse/releases/tag/v1.33.2","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Release Notes","Third Party Advisory"]},{"url":"https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch","Third Party Advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/","source":"af854a3a-2127-422b-91ae-364da2661108"}]}}]}