{
  "id": "CVE-2021-29471",
  "sourceIdentifier": "security-advisories@github.com",
  "published": "2021-05-11T15:15:08.507",
  "lastModified": "2022-04-05T18:06:54.547",
  "vulnStatus": "Analyzed",
  "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 dom\u00e9stico de referencia de Matrix escrito en python (paquete pypi matrix-synapse). Matrix es un ecosistema para VoIP y mensajer\u00eda instant\u00e1nea federada abierta. En Synapse versiones anteriores a 1.33.2, unas \"Push rules\" pueden especificar condiciones bajo las cuales coincidir\u00e1n, incluyendo \"event_match\", que compara el contenido del evento con un patr\u00f3n que incluye comodines. Determinados patrones pueden causar un rendimiento muy deficiente en el motor de coincidencia, conllevando a una denegaci\u00f3n de servicio cuando se procesan eventos de duraci\u00f3n moderada. El problema est\u00e1 parcheado en versi\u00f3n 1.33.2. Una posible soluci\u00f3n alternativa podr\u00eda ser impedir a unos usuarios crear reglas de inserci\u00f3n personalizadas, al bloquear dichas peticiones en un proxy inverso"
    }
  ],
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          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "LOW",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM"
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        "exploitabilityScore": 3.9,
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          "accessVector": "NETWORK",
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        },
        "baseSeverity": "MEDIUM",
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      "type": "Primary",
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          "value": "CWE-331"
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  "references": [
    {
      "url": "https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c",
      "source": "security-advisories@github.com",
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    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/",
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