Denial of Service (DoS) Affecting io.netty:netty-codec-http package, versions [0,4.1.53.Final)



    Attack Complexity Low
    Availability High

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  • Snyk ID SNYK-JAVA-IONETTY-1020439
  • published 21 Oct 2020
  • disclosed 10 Sep 2020
  • credit Unknown

How to fix?

Upgrade io.netty:netty-codec-http to version 4.1.53.Final or higher.


io.netty:netty-codec-http is a network application framework for rapid development of maintainable high performance protocol servers & clients.

Affected versions of this package are vulnerable to Denial of Service (DoS). When the post request body data received by the server is greater than 16k, netty will use DiskAttribute, which will create a temporary file, and use deleteOnExit() when the file needs to be deleted, which results in DeleteOnExitHook.files continually growing and leading to a denial of service.


Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package