Denial of Service (DoS) Affecting io.netty:netty-codec package, versions [,4.1.68.Final)



    Attack Complexity Low
    Availability High

    Threat Intelligence

    EPSS 0.33% (68th percentile)
Expand this section
7.5 high
Expand this section
Red Hat
7.5 high

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  • Snyk ID SNYK-JAVA-IONETTY-1584064
  • published 11 Sep 2021
  • disclosed 9 Sep 2021
  • credit Ori Hollander of JFrog Security

How to fix?

Upgrade io.netty:netty-codec to version 4.1.68.Final or higher.


io.netty:netty-codec is an event-driven asynchronous network application framework.

Affected versions of this package are vulnerable to Denial of Service (DoS). Bzip2Decoder doesn't allow setting size restrictions for decompressed data. An attacker can exploit this by providing a compressed file that, when decompressed, triggers an out-of-memory exception.


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