Denial of Service (DoS) Affecting package, versions >=1.4.0 <1.5.2



    Attack Complexity Low
    Availability High

    Threat Intelligence

    EPSS 0.16% (51st percentile)
Expand this section
9.8 critical

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
  • published 24 Jun 2021
  • disclosed 23 Jun 2021
  • credit Unknown

How to fix?

Upgrade to version 1.5.2 or higher.

Overview is a Package web is a HTTP server for Golang applications.

Affected versions of this package are vulnerable to Denial of Service (DoS). Websocket requests did not call AuthenticateMethod. Depending on implementation, a denial-of-service or privilege escalation vulnerability may occur in software that uses the package with Web Sockets that have an AuthenticateMethod.

The AuthenticateMethod is not called, and UserData will be nil in request methods. Attempts to read the UserData may result in a panic. This issue only affects web sockets where an AuthenticateMethod is supplied to the handle options. Users who do not use web sockets, or users who do not require authentication are not at risk.


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