Open Source Software License Risks of Copying Code from Stack Overflow

Software developers must take precaution when copying code from Stack Overflow for use in commercial projects. Otherwise, they may put…

Software developers must take precaution when copying code from Stack Overflow for use in commercial projects. Otherwise, they may put their employers at risk of open source license infringement. Open source software introduced by Stack Overflow poses security, operational, and license compliance risks. How can you still leverage Stack Overflow code and minimize these risks?

If you want to know what the weather is going to be like today, you look at an app or ask your virtual assistant. When you don’t know how to do something DIY related, you search online or watch videos.  

Likewise, if a developer doesn’t know how to code something, they simply search online or on Stack Overflow. Stack Overflow is a community-driven website where developers ask questions and share answers. However, what developers may not realize is that copying code from Stack Overflow without considering the license terms can lead to problems.  

The Stack Overflow terms of service indicate that content, including code, can be copied for personal, non-commercial use only and is subject to the copyleft Creative Commons Attribution-Share Alike 4.0 International (CC BY-SA 4.0) license. Additionally, Stack Overflow from time-to-time releases compilations of content under the same license. This means that developers need to be careful about how they use code from Stack Overflow to ensure they’re complying with the licensing terms. 

What is the CC-BY-SA License?

In a nutshell, the CC-BY-SA license is a type of copyright license used for creative works, including text, images, and other media. It allows creators to share their work with others under certain conditions. Here’s what the CC-BY-SA license entails: 

Attribution (BY): This condition requires anyone using the work to give appropriate credit to the original creator. They must provide a citation or acknowledgment, typically in the form of a link or reference to the original work. 

ShareAlike (SA): This copyleft provision requires anyone adapting, remixing, or transforming the original work to distribute their derivative work under the same CC-BY-SA license terms. In other words, if someone modifies or builds upon the original work, they must release their new creation under the same license. 

The CC-BY-SA license was never intended for use with application source code (software). The Creative Commons Organization even recommends against using Creative Commons licenses for software within their FAQ. 

Will Generative AI Increase or Reduce Open Source License Compliance Risks?

At present we don’t see large language models being trained on content directly from Stack Overflow, however, let’s not forget that the biggest users of open source are the open source community members themselves whereby these developers have copied and pasted from Stack Overflow.

If developers copy code from Stack Overflow into projects on repos that are being used to train Generative AI models, there is the risk that Generative AI may reproduce results that include the code on Stack Overflow. If a Generative AI model delivers a response containing a snippet of this code, then one is by definition modifying or building upon the original work. If this code is further integrated into a proprietary work, it could have major consequences because of the CC-BY-SA license.

How Can You Copy-Paste Code from Stack Overflow and Minimize Risks?

Considering the license risks associated with copying and pasting code from Stack Overflow, it’s important to integrate effective detection mechanisms into the developer lifecycle. Granular and accurate code snippet detection technology backed by a comprehensive and up-to-date knowledge base is necessary. FossID uniquely provides this capability and enables developers to proactively identify Stack Overflow snippets and assess their licensing implications upfront, mitigating potential compliance challenges downstream in their CI/CD process.

How Does FossID Detect Stack Overflow Code Snippets?

The FossID Knowledge Base encompasses a vast repository of over 200 million open source projects sourced not only from public repositories but also from public forums such as Stack Overflow. Consequently, when conducting code scans within FossID, users have the capability to uncover code snippets originating from Stack Overflow discussions. 

In contrast, many other Software Composition Analysis (SCA) and Open Source Audit providers lack the capability to identify code sourced from Stack Overflow. This limitation arises from their inability to harvest content directly from the forum. While some providers may claim to identify Stack Overflow snippets, their methods typically rely on developers explicitly including URLs or comments within the code, which significantly narrows the scope of detection. FossID, however, can capture and analyze code from diverse sources, including Stack Overflow, to conduct more thorough and accurate open source software compliance assessments for organizations. 

Additional Resources for Open Source Software License Compliance

For more information on open source software license compliance and code snippet detection, check out these resources. 

Gary Armstrong, Senior Director of Operations (EMEA) and Head of Professional Services  

Gary Armstrong is dedicated to empowering businesses to harness the benefits of open source software while ensuring legal compliance and security confidence. Backed by more than a decade of experience delivering open source security and compliance services, Gary shares his insights and best practices through writing and speaking engagements with the open source community. 

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