Denial of Service (DoS) Affecting petero.cbor package, versions [, 4.5.1)

  • Attack Complexity


  • Availability


Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • snyk-id


  • published

    23 Jan 2022

  • disclosed

    21 Jan 2022

  • credit


How to fix?

Upgrade PeterO.Cbor to version 4.5.1 or higher.


PeterO.Cbor is a C# implementation of Concise Binary Object Representation (CBOR).

Affected versions of this package are vulnerable to Denial of Service (DoS) via an inefficient algorithm when a maliciously crafted input is passed to DecodeFromBytes or other CBOR decoding mechanisms.


An input that decodes to a single CBOR object is not capable of containing a CBOR map if:

  1. It begins with a byte other than 0x80 through 0xDF, or
  2. It does not contain a byte in the range 0xa0 through 0xBF Such an input is not affected by this vulnerability and an application can choose to perform this check before passing it to a CBOR decoding mechanism.


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