Guide to Vulnerability Severity Levels

A normal company, a normal software, a normal enterprise has dozens of vulnerabilities — some inherent to their system, which they simply can’t fix, just mitigate, some which have been coded – by bad practices or intention into their infrastructure, and some which came about accidentally. How do you determine vulnerability severity? Which one do you fix first? You have to find the right balance between your budget, your manpower, and your infrastructure and decide what problem to tackle first — which is a simple challenge, and which one is an apocalypse level event. That’s why it is important to have benchmarks in place and criteria that determine your vulnerability severity. 

What is vulnerability severity? 

Vulnerability severity is a measure of the level of risk that a vulnerability poses to an organization and its customers. It is important to know the severity of the vulnerability to determine whether it should be fixed immediately or if it can wait until a later date. To learn more about how do you determine a vulnerability severity, go to the site:

Today, thanks to how the industry has evolved, vulnerability severity ratings have become standardized. The sale is a free and open industry standard, commonly shortened as CVSS (Common Vulnerability Scoring System). CVSS aims to designate severity scores to those weaknesses that have become a trend in the industry — allowing teams to prioritize response and resources. Scores are calculated, in many cases automatically, based on a formula that takes into account the ease of attack, the opportunity of attack, and the general impact of an exploit. Scores range from 0 to 10 — and are then correlated to vulnerability levels that range from critical to low.

The scale was implemented by the National Infrastructure Advisory Council (NIAC) with the help of the Forum of Incident Response and Security Teams (FIRST) in April 2005. It is constantly being reworked and updated to today’s threats and technological changes. 

What is a vulnerability severity rating based on?

A vulnerability severity rating is a measure of the potential impact that a vulnerability can have on an application. It is usually assigned by software developers, security professionals, and other IT professionals.

The severity of a vulnerability is determined by how easily it can be exploited and the potential damage it can cause to an application or network. The most common scale for measuring the severity of vulnerabilities is CVSS v3, which takes into account three key factors:

-The exploitability of the vulnerability

-The extent or scope of the vulnerability

-The degree of user interaction necessary to exploit the vulnerability

Determining Vulnerability Rating

How do you determine a vulnerability severity? Today, the Common Vulnerability Scoring System (CVSS) is in its third iteration — Version 3.1 to be exact. Several metrics have been changed, as well as new ones integrated. It retains the initial scoring range of 0.10. As a whole, CVSS calculation takes into account the following metrics:

  • Access Vector: shows how vulnerabilities can be exploited.
  • Access Complexity: describes how easy or hard is it to exploit a vulnerability.
  • Authentication: takes into account how many attacks have to be performed to exploit a vulnerability.
  • Confidentiality: describes the impact of the attack on private data.
  • Integrity: takes into account how an attack hurts the integrity of a system.
  • Availability: describes how an attack impacted the availability of a system — bandwidth, process cycles, memory, and other digital resources. 

These metrics are then used to calculate and score the effect of a vulnerability on your company if exploited. Based on the results of the formula, your vulnerabilities are classified into 4 categories — by their rating 0 to 10.

  • None: 0 rating.
  • Low: 0.1 to 3.9 rating.
  • Medium: 4.0-6.9 rating.
  • High: 7.0-8.9 rating.
  • Critical: 90.10.0 rating.


These types of vulnerabilities normally have the following features:

  • They are the result of a root-level compromise of servers or a huge problem with the overall infrastructure of your company. 
  • In many cases, exploitation is fast and pretty straightforward — the attacker doesn’t have to jump through hoops to comprise your systems.  

These types of vulnerabilities have to be patched up ASAP. 


These kinds of vulnerabilities are difficult to exploit, yet, if they are breached or taken advantage of, they could result in giving attackers elevated privileges. They could also evolve into nightmare scenarios, as such an exploration makes you vulnerable to significant data loss, and downtime. 


These are the most common vulnerabilities in the industry. When you think of ransomware, social engineering, malware, Denial of Service Attacks, etc those are threats that have a direct correlation to this security level. 

These types of vulnerabilities have some or more of the following characteristics.

  • The attacker will manipulate employees via social engineering tactics. 
  • When Denial of Service vulnerabilities are difficult yet not impossible to set up.
  • Attackers need to have access to a victim’s local network.
  • Vulnerabilities will only give you attacker limited access — they can only hurt you so much. 
  • These types of vulnerabilities require privileges to be exploited successfully.

In general, these types of vulnerabilities, those that reside in this spectrum, are normally combated through security training. Your employees are the ones being targeted in this stage. 


These kinds of vulnerabilities normally have little to no impact on your organization’s business. They can be exploited by normally requiring local or physical access to a network. It’s important to patch them up since they can evolve into a problem but, as a whole, you can take your time. 

Why are vulnerability security levels important?

Vulnerability security levels give you an idea of how exposed your organization is to a threat or an attack. It can help you categorize and prioritize patches and updates — and where to funnel your capital to. Generally speaking, most organizations need constant supervision when it comes to vulnerabilities, and most of that focus will be placed on your medium to high vulnerabilities? Why, because they are the ones that are normally exploited by hackers. They stand on the bell curve. Critical vulnerabilities should be fixed rapidly but they hardly ever show up or are exploited. While low vulnerabilities can be easily exploited, in many cases the hacker won’t get anything of value from the feat.


TBN Editor

Time Business News Editor Team