Developers turn to open-source software (OSS) for its flexibility, transparency, and community-driven innovation. It powers everything from small utilities to global enterprise systems. But the same openness that makes OSS so valuable can also introduce risk. Vulnerabilities, unvetted contributors, and outdated components can quietly slip into your codebase, creating security gaps that may go unnoticed until it’s too late.
For security leaders and developers alike, staying aware of these OSS threats is integral to protecting the software supply chain throughout the software development lifecycle (SDLC). In this guide, we’ll examine some of the top open-source software risks and how to reduce them without slowing development.
What Is Open-Source Software?
Open-source software makes its source code freely available, giving anyone the ability to review and audit it. This transparency contrasts sharply with proprietary software, where source code remains hidden behind vendor walls.
Organizations turn to open-source software for flexibility, cost savings, and freedom from vendor lock-in. But OSS isn’t created equally. Some projects are actively maintained, while others quietly stall. And while many assume more eyes on the code means better security, that’s not always the case.
The open nature of OSS invites collaboration, but it also varies widely in oversight and quality. That openness has enabled some of the world’s most widely used tools, including Linux and WordPress. Fixes, features, and peer reviews from the open-source community continue to drive innovation.
Still, visibility doesn’t guarantee scrutiny. Even widely used packages—prebuilt collections of code that developers use to add functionality—can contain unnoticed vulnerabilities. Once included in a build, those components become part of your software supply chain security posture, making it all the more important to track, vet, and manage what’s under the hood.
10 Open-Source Software Risks
As open source becomes the default for modern software development, it’s also drawing more attention from attackers. With open-source components embedded in everything from internal tools to customer-facing apps, they’ve become a high-value target. And because many OSS components are common across various ecosystems, a single exploit can have far-reaching consequences.
Not every open-source project poses a threat, but it’s not always easy to tell which ones are safe. Visibility is key. Knowing what to watch for is the first step in choosing packages that won’t add friction or introduce downstream risk.
The following 10 open-source software security risks show how unmanaged OSS can expose hidden vulnerabilities and threaten the integrity of your software supply chain.
1. Compromise of Legitimate Package
Attackers don’t always build their malware from scratch. Sometimes, they hijack trusted packages by compromising a project maintainer's credentials or breaching the distribution infrastructure and repository systems. Once inside, they quietly inject malicious code into an update, letting it slip through what looks like a secure channel. This was the case in an event-stream incident, where malicious code sat undetected in a popular NPM package that millions used.
2. Vulnerabilities Are Public Domain
In OSS, vulnerabilities often surface in public forums or databases like the National Vulnerability Database (NVD). This visibility helps defenders respond faster, but it also gives attackers an equal opportunity to act first. The longer a patch goes without implementation, the higher the risk of exploitation. A well-known example is Log4Shell, a critical flaw in the widely used Java logging library Log4j. Once publicly known, the vulnerability gave attackers a way to run remote code on millions of servers, forcing emergency responses across industries.
3. Name-Confusion Attacks
Also known as typosquatting or brandjacking, these attacks trick developers into downloading fake packages that closely resemble legitimate ones. A single character—or a familiar-sounding author—is all it takes for a rogue library to slip into the codebase.
These malicious packages often hide backdoors or data-harvesting logic behind what looks to be standard functionality. One notable case, a dependency confusion attack, exploited the gap between public and private package registries. Attackers uploaded impostor packages to public repositories using the same names as internal ones. When build tools pulled from the public registry by default, the fake packages infiltrated enterprise systems—successfully breaching companies like Apple and Microsoft.
4. Untracked Dependencies
Modern apps rely on dozens or sometimes hundreds of transitive dependencies, many of which receive no direct review. Without full dependency scans or a regularly updated Software Bill Of Materials (SBOMs), risky components can move through the pipeline unnoticed, posing threats to software supply chain security.
5. Outdated or Unmaintained Code
Adding an open-source package is easy, but tracking it over time takes work. When a project slows down or loses its maintainers, that once-helpful code can quietly drift into unmaintained territory. According to the Open Worldwide Application Security Project (OWASP), many vulnerable packages are in use for years after support ends. This slow creep of "security debt" compounds risk over time, especially in large codebases.
6. License and Legal Pitfalls
Open-source licenses vary widely, from permissive to restrictive. Some require public disclosure of any modifications, which can clash with business models that rely on proprietary code. Misunderstanding or ignoring these terms can introduce serious legal risks.
7. Immature or Low-Quality Projects
Some projects lack a mature development process—they skip testing and have no versioning system or meaningful documentation. Even if the code technically works, poor development practices make identifying vulnerabilities and ensuring reliability harder. Without guardrails, you may need to rely more heavily on security code review tools to catch issues early.
8. Inadequate Version Pinning
To simplify upgrades, developers sometimes allow loose version ranges in dependencies. But this flexibility can backfire, pulling in unstable updates or introducing new vulnerabilities without warning. Without strict version pinning, a single change upstream can ripple through your codebase unexpectedly.
9. Overprivileged Packages
Some packages ask for more permissions than they actually need, which is why it’s important to evaluate whether their functionality really requires access to environment variables, network calls, or sensitive files. By following the principle of least privilege, teams can minimize unnecessary exposure and reduce the blast radius if any vulnerability is exploited.
10. Lack of Provenance
Open-source software is often transparent—but not always verifiable. If you can’t confirm where a package came from, who really authored it, or how the code was compiled, you’re flying blind. Without trustworthy metadata or provenance, it’s harder to assess the authenticity of what you’re installing.
That uncertainty creates opportunities for attackers. Without signed artifacts or traceable authorship, bad actors can impersonate maintainers, publish lookalike packages, or inject malicious code into popular repos. And when there’s no clear chain of custody, it’s more difficult to detect tampering.
4 Features of an Assured Open-Source Software
Knowing what good OSS looks like helps you make smarter decisions when evaluating tools for software supply chain security. These four features reflect how open-source software security best practices show up in real-world packages—and what teams should expect from any OSS they bring into production.
1. Provides Detailed Data
Assured open-source packages come with verifiable metadata. Signed SBOMs and Vulnerability Exploitability eXchange (VEX) documents give you visibility into every part of the package, including transitive dependencies. They clarify exactly what you're using and how developers built it.
2. Is Developer-Friendly
Safe OSS packages follow secure development practices, reducing risk without slowing teams down. Frameworks like Supply-chain Levels for Software Artifacts (SLSA) help developers build, scan, and track their dependencies with confidence. When teams work this way, they can trust what they’re pulling in and spend less time worrying about hidden malicious code.
3. Uses Verified and Secure Distribution
Developers don’t just approve OSS and hope for the best—it travels through secure, signed distribution channels that verify integrity and prevent tampering. This tamper-evident provenance ensures that the code you install matches what was reviewed, approved, and intended.
4. Aligns With Compliance and Supply Chain Standards
Strong open-source software security goes hand-in-hand with compliance. Beyond aligning with frameworks like SLSA, trusted OSS projects meet the expectations of security regulations like the Payment Card Industry Data Security Standard (PCI-DSS) and the Sarbanes-Oxley Act (SOX). This makes it easier to bring open source into regulated environments without compromising your security posture.
How to Reduce Open-Source Software Risks
You can’t eliminate every threat, but you can reduce the likelihood and impact of issues with open-source software by taking a few smart steps:
- Scan code with Software Composition Analysis (SCA) tools: SCA tools give you visibility into your codebase, including transitive dependencies, licensing obligations, and known vulnerabilities. They’re one of the fastest ways to catch outdated packages or compliance gaps before they become security incidents.
- Perform in-depth licensing reviews: Before adding a new component to your stack, check its open-source license and make sure your team understands the terms. Some licenses may conflict with proprietary software or impose redistribution requirements that could land you in legal trouble.
- Create a regular update schedule: Outdated or unmaintained components are common attack vectors. Set a schedule to monitor security advisories and replace unsupported libraries with trusted, actively maintained alternatives.
- Train developers on open-source security practices: Not every issue stems from external packages. Training devs to avoid hardcoded secrets, validate inputs, and control dependency sprawl matters just as much as how you configure and use your scanning tools. These habits often make the difference between a secure build and one that quietly inherits risk.
Ensure Open-Source Software Security With Legit Security
Legit Security makes integrating OSS easy—without sacrificing visibility or control. By embedding security checks directly into your CI/CD workflows, Legit helps you spot risky packages early, track OSS usage across projects, and stay aligned with both internal policies and external compliance standards.
Get ahead of OSS risk with built-in visibility and control. Book a demo to see how Legit can help.