CVE-2026-39304: Apache ActiveMQ Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5568-6qcg-g7fx",
  "modified" : "2026-04-10T21:01:01Z",
  "published" : "2026-04-10T12:31:44Z",
  "aliases" : [ "CVE-2026-39304" ],
  "summary" : " Apache ActiveMQ: Denial of Service via Out of Memory vulnerability",
  "details" : "Denial of Service via Out of Memory vulnerability in Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ.\n\nActiveMQ NIO SSL transports do not correctly handle TLSv1.3 handshake KeyUpdates triggered by clients. This makes it possible for a client to rapidly trigger updates which causes the broker to exhaust all its memory in the SSL engine leading to DoS.\n\nNote: TLS versions before TLSv1.3 (such as TLSv1.2) are broken but are not vulnerable to OOM. Previous TLS versions require a full handshake renegotiation which causes a connection to hang but not OOM. This is fixed as well.\nThis issue affects Apache ActiveMQ Client: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ Broker: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ: before 5.19.4, from 6.0.0 before 6.2.4.\n\nUsers are recommended to upgrade to version 6.2.4 or 5.19.5, which fixes the issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.activemq:activemq-client"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.19.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.activemq:activemq-client"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.0"
      }, {
        "fixed" : "6.2.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.activemq:activemq-broker"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.19.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.activemq:activemq-broker"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.0"
      }, {
        "fixed" : "6.2.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.activemq:activemq-all"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.19.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.activemq:activemq-all"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.0"
      }, {
        "fixed" : "6.2.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.activemq:apache-activemq"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.19.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.activemq:apache-activemq"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.0"
      }, {
        "fixed" : "6.2.4"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-39304"
  }, {
    "type" : "WEB",
    "url" : "https://activemq.apache.org/security-advisories.data/CVE-2026-39304-announcement.txt"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/apache/activemq"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/04/09/17"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-10T21:01:01Z",
    "nvd_published_at" : "2026-04-10T11:16:23Z"
  }
}