Denial of Service (DoS)

Affecting rrule package, versions <2.5.6

medium severity


rrule is a JavaScript library for working with recurrence rules for calendar dates as defined in the iCalendar RFC and more.

Affected versions of this package are vulnerable to Denial of Service (DoS) attacks. An attacker trigger an infinite loop, causing the system to stop responding.


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


Upgrade rrule to version 2.5.6 or higher.


Do your applications use this vulnerable package?

David Golightly
Snyk ID
30 Sep, 2018
09 Oct, 2018