Node.js keep-alive HTTP Connections Denial of Service Vulnerability [CVE-2019-5739]

CVE Number – CVE-2019-5739

A vulnerability in Node.js could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.The vulnerability is due to uncontrolled resource consumption by the keep-alive mode of the affected software when established connections remain open for two minutes. An attacker could exploit this vulnerability by establishing an HTTP or HTTPS connection on the targeted system. A successful exploit could result in a DoS condition because the server.keepAliveTimeout function is not implemented in the affected software.Node.js has confirmed the vulnerability and released software updates.


  • To exploit this vulnerability and attacker must have network access and the ability to establish HTTP and HTTPS connections to the targeted system. This requirement could reduce the likelihood of a successful exploitation.


  • Administrators are advised to apply the appropriate updates.Administrators are advised to allow only trusted users to have network access.Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.Administrators can help protect affected systems from external attacks by using a solid firewall strategy.Administrators are advised to monitor affected systems.

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Duncan Newell

Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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