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CWE Top 10 Most Dangerous Software Weaknesses for 2023


Discover the top 10 critical software weaknesses in 2023 according to MITRE CWE. Prevent attacks by developing secure applications protected against these common vulnerabilities in today's blog.

An Introduction to 2023's Top Software Weaknesses

Application security is essential to any organization that uses software. Controlling which applications are running within the environment can help prevent exposure to malicious apps, and patch management is important to ensure that all applications are free from the latest bugs. On the software development side of things, application designers must ensure that security best practices are parts of the architecting and coding phases of software development operations (DevOps) to prevent common software vulnerabilities that can make their application vulnerable to be later exploited by hackers.

For the highest security assurances, software code needs to be manually reviewed and tested using a variety of methods including static and dynamic testing, and using specific techniques such as unit testing, fuzzing, and penetration testing. By implementing in-depth application security testing, organizations can improve an application's resilience against attack and improve the reliability and integrity of their applications.

MITRE has recently published the Top 25 CWE software weaknesses of 2023, highlighting critical vulnerabilities that pose the most significant risks. This list offers software development teams the opportunity to review, update, and enhance their understanding of software vulnerabilities and improve the security of their software.

Firstly, What is Common Weakness Enumeration (CWE)?

Common Weakness Enumeration (CWE) is a framework of structured taxonomy for identifying and categorizing software security weaknesses. Established by the MITRE Corporation, a non-profit organization known for its extensive contributions to technology and defense, the CWE catalog of software threats is built from collaboration between industry experts, security researchers, and software developers. At its core, CWE serves as a central repository of information in a standardized language for describing and classifying these vulnerabilities.

CWE contains over 800 entries organized into a hierarchical structure, with each weakness assigned a unique identifier and categorized based on various attributes such as the nature of the weakness, its potential impact, and the technology it relates to. The structure includes classes, subclasses, and base elements representing specific weaknesses. Each weakness entry in the catalog includes detailed descriptions, examples, potential consequences, and guidance on how to mitigate or prevent the vulnerability.

CWE can be mapped to CVE (Common Vulnerabilities and Exposures) to provide context for understanding specific vulnerabilities. Mapping CWE to CAPEC (Common Attack Pattern Enumeration and Classification) enriches understanding of how attackers exploit these weaknesses through specific attack patterns. Integrating CWE into Secure Development Lifecycle (SDLC) Models is a proactive way to ensure vulnerabilities are identified and mitigated at various stages of software development.

From software developers seeking to fortify their code against potential vulnerabilities to penetration testers and security analysts uncovering weak points in applications, CWE offers a common language and systematic methodology for tackling software weaknesses effectively. By understanding and utilizing CWE's insights, organizations can bolster their defenses against the top 25 most dangerous software weaknesses and enhance their overall cybersecurity posture in an ever-evolving digital landscape.

The CWE Top 10 Most Dangerous Software Weaknesses of 2023

Here are the CWE top 10 most dangerous software weaknesses of 2023.  Of the top 25 list 8 of the weaknesses are caused by improper use sanitization, making this the largest classification of vulnerabilities.  The next highest broad classes are: improperly designed or implemented access controls (authentication or authorization weaknesses), and exploitation of memory processes (such as allocation and deallocation) with six items.

The complete list can be found on the CWE website.  Here is a brief explanation of the top 10:

Top Ten CWE of 2023

  • Out-of-bounds Write (Unchanged): Writing data beyond the boundaries of a memory buffer can allow an attacker to write executable code into memory locations that will later be passed to the CPU and executed.  It’s important to use memory safe languages whenever possible and when it’s not feasible, ensure that functions known to be vulnerable are not used such as malloc(), calloc(), and realloc() for C-style memory allocation.

  • Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting' or 'XSS') (Unchanged): Failure to properly sanitize user inputs in web applications, leading to potential cross-site scripting attacks can allow an attacker to execute Javascript within a victim's browser. This can be avoided by properly encoding user supplied input to HTML entities before including it into a web page. A classic attack against a XSS vulnerability is when an attacker submits JS code as a comment on a webpage, and all visitors to the site will have the attacker's code executed on their browser.

  • Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') (Unchanged): Inadequate input validation in SQL queries can allow malicious SQL commands to be executed.  Always use database functions that use 'prepared statements' to encode user supplied input that is used in a query to avoid executing malicious code. 

  • Use After Free (Up 3 places): Continuation of using memory after it has been released, leading to unpredictable behavior. Memory safe languages incorporate memory management mechanisms that relieve developers from manual memory allocation and deallocation responsibilities.  If using a memory-safe language is not feasible, careful programming practices and strict adherence to memory management best practices are required to mitigate against these vulnerabilities.

  • Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') (Up 1 place): Inadequate input validation in OS commands, enabling attackers to execute unintended commands on the target.  It's best to never allow any client-side data to be included directly in shell commands.  When a use case specifically requires this feature, administrators need to ensure that the underlying virtualization is well protected against escape, allowing an attacker to pivot into the subsystem or other network hosts. 

  • Improper Input Validation (Down 2 places): Insufficient validation of user inputs, potentially leading to various vulnerabilities including injection attacks. This entry is a broad classification that includes all types of weaknesses where user supplied input is not properly sanitized to remove potentially malicious content before it is used. Strict input validation and sanitization is required to mitigate these attacks.

  • Out-of-bounds Read (Down 2 places): Reading data from memory beyond the intended boundaries can allow an attacker to steal sensitive data such as passwords, or encryption keys from memory. Mitigation of this vulnerability is the same as other memory-based items on the list.

  • Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (Unchanged): Failure to properly validate and restrict file paths, can allow attackers to steal or modify unauthorized files or include malicious shared libraries such as DLL files.

  • Cross-Site Request Forgery (CSRF) (Unchanged): Exploitation of authenticated user sessions to perform unwanted actions without their consent. CSRF is a type of attack where an attacker tricks a user into unknowingly performing actions on a web application by crafting malicious requests that appear legitimate, often utilizing the user's existing session cookies or authentication tokens. Attackers could take advantage of a user's website account remotely to make orders, transfer funds, or change other details such as passwords, account email addresses, and more.

  • Unrestricted Upload of File with Dangerous Type (Up): Allowing users to upload potentially malicious files that can be executed on the server. Application developers need to verify not only the file's extension matches the expected type of file, but also verify the file's contents whenever possible.


In a best-case scenario, software vulnerabilities should be a major consideration during the architecting and development of all software applications. In the case that vulnerabilities are included in a published app, they give attackers the opportunity to exploit its users until the problem is detected and patched.  Software developers need to be aware of the potential weaknesses that could be found in software applications in order to proactively prevent them. 

The CWE catalog of software weaknesses provides a common language for developers to learn about software security, and the CWE top 25 is the most current and relevant source of information.

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