TOPIC: CROSS-SITE SCRIPTING
The Open Worldwide Application Security Project: A Cornerstone of Digital Safety in an Age of Evolving Cyber Threats
24th February 2026
When Mark Curphey registered the owasp.org domain and announced the project on a security mailing list on the 9th of September 2001, there was no particular reason to expect that it would become one of the defining frameworks in the world of application security. Yet, OWASP, originally the Open Web Application Security Project, has done exactly that, growing from an informal community into a globally recognised nonprofit foundation that shapes how developers, security professionals and businesses think about the security of software. In February 2023, the board voted to update the name to the Open Worldwide Application Security Project, a change that better reflects its modern scope, which now extends beyond web applications to cover IoT, APIs and software security more broadly.
At its heart, OWASP operates on a straightforward principle: knowledge about software security should be free and openly accessible to everyone. The foundation became incorporated as a United States 501(c)(3) nonprofit charity on the 21st of April 2004, when Jeff Williams and Dave Wichers formalised the legal structure in Delaware. What began as an informal mailing list community grew into one of the most trusted independent voices in application security, underpinned by a community-driven model in which volunteers and corporate supporters alike contribute to a shared vision.
The OWASP Top 10
Of all OWASP's contributions, the OWASP Top 10 remains its most widely cited publication. First released in 2003, it is a standard awareness document representing broad consensus among security experts about the most critical risks facing web applications. The list is updated periodically, with a 2025 edition now published, following the 2021 edition.
The 2021 edition reorganised a number of longstanding categories to reflect how the threat landscape has shifted. Broken access control rose to the top position, reflecting its presence in 94 per cent of tested applications, while injection (which encompasses SQL injection and cross-site scripting, among others) fell to third place. Cryptographic failures, previously listed as sensitive data exposure, took second place. By organising risks into categories rather than exhaustive lists of individual vulnerabilities, the Top 10 provides a practical starting point for prioritising security efforts, and it is widely referenced in compliance frameworks and security policies as a baseline. It is, however, designed to be the beginning of a conversation about security rather than the final word.
Projects and Tools
Beyond the Top 10, OWASP maintains a substantial portfolio of open-source projects spanning tools, documentation and standards. Among the most widely used is OWASP ZAP (Zed Attack Proxy), a dynamic application security testing tool that helps developers and security professionals identify vulnerabilities in web applications. Originally created in 2010 by Simon Bennetts, ZAP operates as a proxy between a tester's browser and the target application, allowing it to intercept, inspect and manipulate HTTP traffic. It supports both passive scanning, which observes traffic without modifying it, and active scanning, which simulates real attacks against targets for which the tester has explicit authorisation.
The OWASP Testing Guide is another widely consulted resource, offering a comprehensive methodology for penetration testing web applications. The OWASP API Security Project addresses the distinct risks that face APIs, which have become an increasingly prominent attack surface, and OWASP also maintains a curated directory of API security tools for those working in this area. For teams managing web application firewalls, the OWASP ModSecurity Core Rule Set provides guidance on handling false positives, which is one of the more practically demanding aspects of deploying rule-based defences. OWASP SEDATED, a more specialised project, focuses on preventing sensitive data from being committed to source code repositories, addressing a problem that continues to affect development teams of all sizes. Projects are categorised by their maturity and quality, allowing users to distinguish between stable, production-ready tools and those that are still in active development, and this tiered approach helps organisations make informed decisions about which tools are appropriate for their needs.
Influence on Industry Practice
The reach of OWASP's guidance is considerable. Security teams use its materials to structure risk assessments and threat modelling exercises, while developers integrate its recommendations into code reviews and secure coding training. Auditors and regulators frequently reference OWASP standards during compliance checks, creating a shared vocabulary that helps bridge the gap between technical staff and leadership. This alignment has done much to normalise application security as a core part of the software development lifecycle, rather than a task bolted on after the fact.
OWASP's influence also extends into regulatory and standards environments. Frameworks such as PCI DSS reference the Top 10 as part of their requirements for web application security, lending it a degree of formal weight that few community-produced documents achieve. That said, OWASP is not a regulatory body and has no enforcement powers of its own.
Education and Community
Education remains a central part of OWASP's mission. The foundation runs hundreds of local chapters across the globe, providing forums for knowledge exchange at a local level, as well as global conferences such as Global AppSec that bring together practitioners from across the industry. All of OWASP's projects, tools, documentation and chapter activities are free and open to anyone with an interest in improving application security. This open model lowers barriers for those starting out in the field and fosters collaboration across academia, industry and open-source communities, creating an environment where expertise circulates freely and innovation is encouraged.
Limitations and Appropriate Use
OWASP is not without its limitations, and it is worth acknowledging these clearly. Because it is not a regulatory body, it cannot enforce compliance, and the quality of individual projects can vary considerably. The Top 10, in particular, is sometimes misread as a comprehensive checklist that, once ticked off, certifies an application as secure. It is not. It is an awareness document designed to highlight the most prevalent categories of risk, not to enumerate every possible vulnerability. Treating it as a complete audit framework rather than a starting point for more in-depth analysis is one of the most common mistakes organisations make when engaging with OWASP materials.
The OWASP Top 10 for Large Language Model Applications
As artificial intelligence has moved from research curiosity to production deployment at scale, OWASP has responded with a dedicated framework for the security risks unique to large language models. The OWASP Top 10 for Large Language Model Applications, maintained under the broader OWASP GenAI Security Project, was first published in 2023 as a community-driven effort to document vulnerabilities specific to LLM-powered applications. A 2025 edition has since been released, reflecting how quickly both the technology and the associated threat landscape have evolved.
The list shares the same philosophy as the web application Top 10, using categories to frame risk rather than enumerating every individual attack variant. Its 2025 edition identifies prompt injection as the leading concern, a class of vulnerability in which crafted inputs cause a model to behave in unintended ways, whether by ignoring instructions, leaking sensitive information or performing unauthorised actions. Other entries cover sensitive information disclosure, supply chain risks (including vulnerable or malicious components sourced from model repositories), data and model poisoning, improper output handling, excessive agency (where an LLM is granted more autonomy or permissions than its task requires) and unbounded consumption, which addresses the risk of uncontrolled resource usage leading to service disruption or unexpected cost. Two categories introduced in the 2025 edition, system prompt leakage and vector and embedding weaknesses, reflect lessons learned from real-world RAG deployments, where retrieval-augmented pipelines have introduced new attack surfaces that did not exist in earlier LLM architectures.
The LLM Top 10 is distinct from the web application Top 10 in an important respect: because the threat landscape for AI applications is evolving considerably faster than that of traditional web software, the list is updated more frequently and carries a higher degree of uncertainty about what constitutes best practice. It is best treated as a living reference rather than a settled standard, and organisations deploying LLM-powered applications would do well to monitor the GenAI Security Project's ongoing work on agentic AI security, which addresses the additional risks that arise when models are given the ability to take real-world actions autonomously.
An Ongoing Work
In an era defined by rapid technological change and an ever-expanding threat landscape, OWASP continues to occupy a distinctive and valuable position in the world of application security. Its freely available standards, practical tools and community-driven approach have made it an indispensable reference point for organisations and individuals working to build safer software. The foundation's work is a practical demonstration that security need not be a competitive advantage hoarded by a few, but a collective responsibility shared across the entire industry.
For developers, security engineers and organisations navigating the challenges of modern software development, OWASP represents both a toolkit and a philosophy: that improving the security of software is work best done together, openly and without barriers.