CWE, or Common Weakness Enumeration, is a community-developed list of software and hardware weaknesses that can lead to security vulnerabilities. Unlike CVE (Common Vulnerabilities and Exposures), which documents specific, real-world vulnerabilities, CWE focuses on underlying flaws in code, architecture, or configuration that attackers often exploit.
Maintained by the MITRE Corporation with support from industry partners and the U.S. Department of Homeland Security, the CWE project provides a standardized language and structure for identifying, discussing, and preventing common software errors across the development lifecycle.
What is CWE?
CWE is a catalog of common software and hardware weaknesses that represent the root causes of security vulnerabilities. Each weakness is assigned a unique identifier (e.g., CWE-89) along with a detailed description, examples, and information about potential mitigations.
Rather than cataloging specific instances of vulnerabilities like CVEs, CWE focuses on types of flaws—such as improper input validation, insecure design patterns, or buffer overflows. These weaknesses can appear across many different applications, platforms, or environments, and understanding them is essential for building secure software.
Each CWE entry typically includes:
- A CWE ID and name (e.g., CWE-79: Improper Neutralization of Input During Web Page Generation – “Cross-site Scripting”)
- A detailed description of the weakness
- Modes of introduction (how it typically appears in software)
- Common consequences and exploitation paths
- Detection methods and remediation guidance
- Relationships to other weaknesses or higher-level categories
How CWE supports secure development
CWE is widely used by software developers, security engineers, vulnerability researchers, and educators to improve the security and reliability of code. It helps teams understand:
- What kinds of mistakes lead to vulnerabilities
- Where those mistakes are most likely to occur
- How to fix or prevent them before deployment
Rather than reacting to individual CVEs after they’ve been disclosed, organizations can use CWE to proactively address classes of weaknesses during development and testing. This approach is foundational to secure-by-design and shift-left security initiatives.
CWE is also used as a benchmark in application security testing tools, training programs, and vulnerability scoring frameworks. For example, the OWASP Top 10 is based on specific CWE entries that correspond to the most dangerous categories of web application flaws.
The CWE hierarchy and structure
The CWE system is organized into a multi-level hierarchy that reflects relationships between weaknesses, patterns, and higher-level categories. At the top level, CWEs are grouped into broad areas such as:
- Design weaknesses – architectural decisions that create systemic security flaws (e.g., CWE-209: Information Exposure Through an Error Message)
- Implementation weaknesses – coding mistakes that lead to issues like memory corruption or injection (e.g., CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer)
- Configuration weaknesses – security issues caused by incorrect system or application configurations (e.g., CWE-16: Configuration)
Each category includes more specific weaknesses, and many CWEs are interconnected through parent-child or peer relationships. MITRE maintains an up-to-date CWE List, which currently includes more than 900 entries and is used as a reference across the cybersecurity community.
The difference between CWE and CVE
While CWE and CVE are often mentioned together, they serve distinct roles in the vulnerability ecosystem.
CVE refers to specific, real-world vulnerabilities in software or firmware. For example, CVE-2021-44228 describes the Log4Shell vulnerability in Apache Log4j. In contrast, CWE focuses on the underlying type of issue that enables such vulnerabilities—in this case, a failure to properly validate input or handle data securely.
CVE is typically used by incident responders, vulnerability management teams, and patch management systems to track and remediate actual flaws in deployed systems. CWE, on the other hand, is used by developers, architects, and security engineers to prevent those flaws from being introduced in the first place.
In simple terms:
- CVE answers: “What specific issue exists in this software right now?”
- CWE answers: “What type of mistake led to that issue, and how can we avoid it?”
Together, CVE and CWE offer a full-spectrum view of vulnerabilities—from root cause to real-world impact.
Use cases for CWE in modern software security
CWE is integral to several aspects of modern software security, from training and development to testing and compliance. Key use cases include:
Secure coding education and training
CWE entries provide detailed, categorized examples of common software flaws. Security training programs, certifications, and secure development bootcamps often use CWE as a foundation to teach developers how to avoid introducing vulnerabilities in their code.
Software composition analysis and scanning tools
Security tools such as static application security testing (SAST) and software composition analysis (SCA) often map findings to CWE identifiers. This allows teams to understand not just what issue exists, but the type of programming mistake behind it and how to fix it at the source.
Third-party software evaluation
Organizations evaluating third-party vendors or open source projects often use CWE mappings to assess the types of weaknesses most frequently reported. CWE-based scoring or coverage can help organizations determine whether a vendor follows secure development practices.
Software development lifecycle (SDLC) integration
Integrating CWE into an organization’s SDLC allows for consistent tracking of recurring code issues, more accurate root cause analysis, and better communication between engineering and security teams.
Limitations and challenges
While CWE is a powerful framework, it comes with some limitations:
- Size and complexity: With more than 900 entries and frequent updates, the full CWE list can be overwhelming to navigate.
- Overlapping categories: Some weaknesses have similar definitions or affect multiple stages of the SDLC, leading to ambiguity in classification.
- Tooling limitations: Not all security tools map to CWE in a consistent or transparent way, which can limit the usefulness of CWE data for remediation planning.
Despite these challenges, CWE remains one of the most valuable resources for building security into software from the start and aligning development teams with security best practices.
How Orca Security helps
The Orca Cloud Security Platform enables organizations to detect, prioritize, and remediate cloud vulnerabilities and other risks across AWS, Azure, Google Cloud, Oracle Cloud, Alibaba Cloud, and Kubernetes.
With Orca, development and security teams can:
- Gain full coverage across multi-cloud environments
- Analyze vulnerabilities holistically in the context of your cloud estate and prioritize them effectively using more than 20 vulnerability data sources
- Remediate vulnerabilities fast and easily using AI-driven and assisted options that span the entire application lifecycle
Orca enables teams to enhance their Vulnerability Management programs, reduce alert fatigue, and unify security before and after deployment.
