MITRE has published the updated annual ranking of the Top 25 Most Dangerous Software Weaknesses, better known as the CWE Top 25. The 2025 list is based on an analysis of 39,080 CVE entries disclosed between June 2024 and June 2025, and was compiled with support from HSSEDI and the U.S. Cybersecurity and Infrastructure Security Agency (CISA) as part of the Common Weakness Enumeration (CWE) program.
The ranking does not describe individual vulnerabilities in specific products. Instead, it focuses on recurring classes of weaknesses in software design, implementation, and architecture that routinely lead to exploitable vulnerabilities. These systemic issues underpin real‑world attacks ranging from data theft and session hijacking to remote code execution and denial of service.
What the CWE Top 25 Measures and How It Relates to CVE
Each item in the MITRE ranking is identified by a CWE-XXX code (Common Weakness Enumeration). This should not be confused with CVE (Common Vulnerabilities and Exposures), which catalogs specific publicly disclosed vulnerabilities.
In essence, CWE defines the weakness type (for example, “improper neutralization of input during web page generation”), while CVE describes a concrete vulnerability instance where that weakness appears in a particular product, version, or library. In other words, CWE is the root cause, and CVE is its manifestation in real software.
To build the 2025 CWE Top 25, MITRE correlated thousands of CVEs with their underlying CWE categories and scored each weakness according to two main criteria: prevalence (how often it appears in the CVE dataset) and severity of impact (the potential business and technical damage when exploited). The combined score determines the position of each weakness in the Top 25.
Key Trends in the MITRE CWE Top 25 for 2025
Cross-Site Scripting (CWE-79) Remains the Top Web Application Weakness
Once again, Cross-Site Scripting (XSS, CWE‑79) leads the list as the most dangerous software weakness. XSS stems from improper validation or neutralization of user-controlled input in web pages, allowing attackers to inject and execute arbitrary JavaScript in the victim’s browser.
Despite years of guidance from OWASP, browser vendors, and security communities, XSS remains widespread. Contributing factors include the explosive growth of complex web applications, extensive use of third‑party frameworks, rapidly changing front‑end stacks, and inconsistent input validation practices. Successful XSS exploitation can enable session hijacking, credential theft, unauthorized actions via CSRF, and content manipulation, often serving as an initial foothold for further compromise.
Authentication and Authorization Weaknesses Grow in Criticality
The 2025 list highlights a sharp increase in the impact of weaknesses related to authentication and authorization, especially in API‑driven and cloud-native environments.
CWE-862: Missing Authorization appears prominently, describing functionality that is accessible without adequate permission checks. This leads directly to vertical and horizontal privilege escalation, where attackers can access other users’ data or perform administrative actions simply because no authorization logic is enforced.
CWE-306: Missing Authentication captures scenarios where services or endpoints operate without verifying user or service identity at all. In microservice architectures and SaaS platforms, such flaws are particularly dangerous: internal APIs assumed to be “trusted” often become reachable from the internet due to misconfiguration, exposing sensitive management operations to unauthenticated attackers.
CISA has repeatedly emphasized in its advisories that broken authentication and missing authorization checks are among the most consistently exploited weaknesses in real attacks against government and critical infrastructure systems, underscoring their inclusion in the Top 25.
Classic Memory Safety Errors Return to the Forefront
The 2025 CWE Top 25 also registers a renewed prominence of memory-related errors traditionally associated with low‑level languages like C and C++. These include stack and heap buffer overflows, null pointer dereference (CWE‑476), improper access control, and uncontrolled resource allocation.
While memory-safe languages such as Rust, Go, and modern Java or .NET reduce the likelihood of such bugs at runtime, a substantial portion of operating systems, embedded devices, telecoms equipment, and industrial control systems still rely on C/C++. For these domains, memory corruption can enable arbitrary code execution, sandbox escape, and reliable denial-of-service attacks. Past high‑impact incidents in browsers, VPN appliances, and network infrastructure have repeatedly traced back to these classes of weaknesses, which explains their persistent presence in the Top 25.
How Organizations Should Use the CWE Top 25 in Security Programs
According to CISA and MITRE, the CWE Top 25 reflects the weakness patterns that attackers most frequently and successfully exploit. As a result, it can serve as a practical roadmap for both secure software development and vulnerability management.
1. Embed CWE Top 25 into “Secure by Design” practices. Architects and product teams should explicitly check new designs against these high‑risk weakness categories: authentication and authorization models, input validation, error handling, session management, and resource governance. Using CWE as a design checklist helps prevent structural flaws before any code is written.
2. Align testing and code review with high‑risk CWE categories. Security testing strategies—static analysis (SAST), dynamic analysis (DAST), and interactive testing—should be tuned to detect the CWE Top 25. Manual code reviews and penetration tests should prioritize these patterns, using CWE identifiers in checklists and test case descriptions to ensure consistency across teams and tools.
3. Prioritize remediation in vulnerability management. When triaging findings from scanners or bug bounty programs, weaknesses mapped to the CWE Top 25 should receive elevated priority, especially in systems processing personal data, payment information, or mission‑critical business processes. Mapping vulnerabilities to CWE categories also helps quantify systemic risk and track trends over time.
4. Train development and security teams using CWE. Educating engineers on the difference between CWE (weakness type) and CVE (specific vulnerability), and on how common weaknesses lead to incidents, enables more effective prevention. Training should include secure coding patterns, framework‑level defenses, and real-world case studies aligned with Top 25 categories.
Regularly consulting the official MITRE CWE Top 25 and treating it as a living “risk map” enables organizations to harden applications at the design and implementation stages, rather than reacting only after incidents occur. In an environment where vulnerability volume continues to grow and attack tooling becomes more automated, focusing security efforts on the most dangerous software weaknesses is a critical step toward a mature and resilient cybersecurity posture.
