Denial of Service (DoS) Affecting yajl-ruby Open this link in a new tab package, versions <1.4.2

  • Attack Complexity


  • Availability


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  • snyk-id


  • published

    6 Apr 2022

  • disclosed

    6 Apr 2022

  • credit

    John Hawthorn

How to fix?

Upgrade yajl-ruby to version 1.4.2 or higher.


Affected versions of this package are vulnerable to Denial of Service (DoS) due to an integer overflow which leads to subsequent heap memory corruption when dealing with large (~2GB) inputs.

The reallocation logic at yajl_buf.c#L64 may result in the need 32bit integer wrapping to 0 when need approaches a value of 0x80000000 (i.e. ~2GB of data), which results in a reallocation of buf->alloc into a small heap chunk.


If upgrading to the fixed version is not possible, avoid passing large inputs to YAJL As a workaround.


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