Legal Risks Arising from the Misuse of Open Source Software

The use of open-source software is not free and unrestricted. Misuse of licenses such as GPL, AGPL, MPL, and Apache can lead to copyright infringement, damages, penalties, contractual liability, and legal risks for company executives. Examine the consequences of open-source license violations in Turkish law in detail.

Contrary to what many companies believe, open-source software does not mean "ownerless," "public domain," or "free code that you can use as you wish." According to the Open Source Initiative, open source is not just about access to the source code; the software's distribution terms must meet certain criteria. Similarly, OSI-approved licenses permit the use, modification, and sharing of software, but only within the terms of the license. Therefore, there is freedom in the open-source world, but not anarchy. For this very reason, the misuse of open-source code can have serious consequences under Turkish law in the areas of copyright, contract, compensation, data security, and corporate liability.

One of the biggest mistakes companies can make is acting without knowing the differences between open-source licenses. Licenses like GPL, AGPL, MPL, and Apache don't all produce the same result. For example, GPL v3 requires the preservation of copyright notices, the provision of the license text, and the continued availability of the modified work in its entirety under the same license when transferring copies of the source code or modified versions of the software. AGPL, in addition, aims to make the relevant source code available to users in modified versions that run publicly over a network. MPL 2.0 focuses on sharing changes, especially in MPL-licensed files, with a "file-level copyleft" approach; Apache 2.0 offers a more relaxed model but still requires the preservation of the license text and typically the NOTICE information. Therefore, simply saying "I used open source" is not legally sufficient; which license is used and what obligations that license entails is the determining factor.

In Turkish law, the fundamental basis for this issue is the Law No. 5846 on Intellectual and Artistic Works. In this law, a "computer program" is defined as a sequence of commands and related preparatory work that enables a computer to perform a specific operation or task. The same law explicitly lists computer programs among "scientific and literary works." Furthermore, the right of reproduction encompasses the acts of loading, viewing, running, transmitting, and storing a computer program. Within this framework, the inclusion of an open-source code fragment into a product under an incorrect license is not merely considered a "labeling error"; in the specific case, it can be evaluated as a direct interference with the financial rights of the work.

One of the most critical misconceptions here is the idea that "if the code is on GitHub, it's free." However, according to the Ministry of Culture and Tourism, ideas are not protected; what is protected is the product that has already been created and qualifies as a work. In computer programs, the author is, as a rule, the person or persons who wrote the source code. For companies, it is also important who will use the financial rights on the works produced within the business relationship. According to Article 18 of the Law on Intellectual and Artistic Works, unless otherwise stipulated in the contract or the nature of the work, the financial rights on the works created by civil servants, employees, and workers in the course of their work are used by those who employ them. The Ministry's optional registration explanations also show that in computer programs, the author is the real person who wrote the source code; companies, on the other hand, can act as the rights holder or user of financial rights under certain conditions.

Therefore, open source license infringement often creates a two-tiered problem. The first tier is the breach of the license terms. The second tier is the debate over whether use becomes unauthorized once the license terms are violated. For example, MPL 2.0 stipulates that rights automatically terminate if the license terms are not complied with; however, they may be reinstated under certain conditions if compliance is subsequently restored. The GPL also requires that the same freedoms be granted to recipients when distributing the software, and that access to the source code be preserved. Therefore, when license compliance is broken, the file is no longer just a matter of "open source compliance"; it can raise a claim of unauthorized use under the Turkish Copyright Law (FSEK). This is not a mechanical formula that automatically produces a result in every case; however, the link between license infringement and FSEK protection is very strong in practice.

One of the most common violations of open-source software is the removal of license and copyright notices. GPL v3 requires that appropriate copyright notices and license warnings be preserved in copies. MPL 2.0 also imposes restrictions on the removal or alteration of notices in the source code. In the case of Apache 2.0, it is expected that a license copy be included in the work and that the NOTICE information be preserved. Companies deleting these texts, considering them "unnecessary clutter," when including third-party packages in a project, can directly constitute a license violation, especially in distributed products. While such violations may not impair the technical functionality of the software, they seriously damage its legal standing.

The second major risk is the misinterpretation of the copyleft effect. In terms of MPLs, copyleft is file-based; according to Mozilla's own explanation, the MPL applies to files containing MPL-enabled code, and new, separate files are not automatically pulled under the MPL. In contrast, the same explanation for GPLs emphasizes that the copyleft effect extends more broadly to "all software based on GPL-enabled code." In practice, companies often overlook this difference; they assume that embedding a GPL component into a closed-source commercial product and simply publishing the relevant folder will suffice. However, if the scope of the license is misanalyzed, a compliance problem can arise that spreads throughout the entire product. Therefore, at the heart of the open-source risk lies not only technical integration but also the correct understanding of the licensing architecture.

The third major risk is the underestimation of the AGPL in SaaS and cloud services. Many companies assume that because they don't use traditional distribution, they don't have an obligation to open the source code. However, this is precisely where the purpose of the GNU AGPL comes into play: it aims to make the source code of a modified version running on a publicly accessible server available to users interacting with that service over the network. Therefore, AGPL compliance is critical, especially for companies developing AI services, control panels, CRM tools, data analytics dashboards, and customer portals. The defense of "we don't provide the program to the customer as a file" is not sufficient on its own in scenarios where the AGPL is used.

The fourth risk is managing open-source code without distinguishing between "private use" within the company and external distribution. According to Mozilla's MPL 2.0 guidelines, private use within the company or organization generally doesn't create a separate distribution obligation; the real obligations become apparent when distribution outside the organization begins. However, if companies draw this line incorrectly—for example, still considering software delivered to group companies, distributors, external contractors, or customers as "internal use"—they are essentially acting without considering the consequences of external distribution. This distinction becomes particularly critical in holding companies, franchise systems, and outsourced software development processes.

Looking at the consequences of private law in Turkish law, the Copyright Law (FSEK) provides quite powerful tools in case of infringement. According to the Ministry of Culture and Tourism, pursuant to Article 68 of the FSEK, the owner of a work whose permission has not been obtained can demand up to three times the amount they would have demanded if a contract had been made, or the market value. In addition, lawsuits for injunction against infringement and for material and moral damages can be filed. The same statement indicates that in cases of infringement of moral and financial rights, the profit obtained by the infringer can also be claimed separately. Although open source licenses generally appear to be free of charge initially, if it is argued that the use has become unauthorized due to a breach of the license terms, claims under the FSEK can be invoked. In the specific case, the scope of the claim varies depending on the type of license, the severity of the infringement, the distribution method, and the proof of damages.

The issue is not limited solely to the Copyright Law. Under the Turkish Code of Obligations, license terms function, at least, as terms of use establishing a legal bond between the parties. According to the Turkish Code of Obligations, a contract is formed by the agreement of the parties' intentions; even if the obligation is not fulfilled at all or properly, the debtor is obligated to compensate the creditor for the damage unless they prove their innocence. Therefore, open source license infringement can create a dispute over both copyright infringement and breach of contractual obligation, depending on the nature of the event. This second layer is often overlooked, especially in corporate supply chains; OEM deliveries, software development contracts, reseller distribution, SaaS contracts, or pre-investment due diligence processes.

The situation is also serious in terms of internal company liability. According to Article 66 of the Turkish Code of Obligations, an employer is obligated to compensate for damages caused by an employee to others during the performance of their work; however, they may be relieved of liability if they prove that they exercised due diligence in selecting, instructing, supervising, and monitoring the employee. The same article also emphasizes whether the company's operational procedures are conducive to preventing such damage. In other words, an integration by a software developer, DevOps employee, or outsourced team that leads to an open-source license violation cannot simply be dismissed as an "individual employee error." If the company lacks a license compliance process, performs dependency scanning, maintains a Business Owner's Office (BOM), has no approval mechanism, and has not established legal-IT coordination, the employer may be liable. Furthermore, Article 116 of the Turkish Code of Obligations explicitly stipulates that leaving the performance of a duty to auxiliary personnel does not automatically absolve the debtor of any damages caused by those auxiliary personnel.

From a corporate governance perspective, open source license compliance is no longer solely the responsibility of the technical team. Article 369 of the Turkish Commercial Code (TTK) states that board members and third parties responsible for management must perform their duties with the diligence of a prudent manager and protect the company's interests according to the rules of honesty. Article 553 of the TTK stipulates that founders, board members, and managers may be held liable for damages caused to the company, shareholders, and creditors if they violate their obligations arising from the law and the articles of association. Therefore, especially in technology companies, SaaS ventures, startups receiving investment, and software exporting firms, failing to establish an open source compliance policy creates not only product risk but also directors' liability risk. This is evaluated according to the specific case, negligence, division of labor, and the standard of diligence.

Misuse of open-source code can sometimes lead to criminal charges. According to the Ministry of Culture and Tourism's copyright infringement guide, the processing, reproduction, distribution, publication, commercial purchase, import or export, possession or storage of works other than for personal use without the written permission of the copyright holder may be subject to criminal prosecution. The same guide also lists the production, sale, or possession (other than for personal use) of software or technical hardware designed to disable additional programs created to prevent the unlawful reproduction of computer programs. In the open-source field, this risk is particularly apparent in interventions made to bypass license control or protective modules. Not every license violation automatically results in a criminal conviction; however, the possibility of a case turning into a criminal investigation should not be underestimated.

The data protection aspect should not be overlooked. Companies must remain within the limits of the Personal Data Protection Law (KVKK) while monitoring code repositories, developer activities, access logs, build logs, and occasionally operating devices for open source compliance. According to KVKK Article 10, the data controller must inform data subjects about their identity, processing purpose, transfer purposes, method of data collection, and legal basis during data collection. KVKK Article 12 regulates the data controller's obligation to take necessary technical and administrative measures and conduct audits to prevent the unlawful processing and access of personal data and to protect the data. Therefore, companies must not violate personal data law while establishing open source license compliance and conducting developer monitoring and compliance audits. Furthermore, if insecure or incorrectly integrated open source components lead to a data breach, a separate KVKK case may arise.

So what are the most common concrete mistakes? First, embedding code snippets found online into the commercial product without checking their license. Second, the developer making GPL or AGPL code part of the closed-source main product and only distributing the binary. Third, removing license text, notice, and source access obligations in Apache or MPL licensed components. Fourth, leaving a component acquired internally for "testing purposes only" in the version sent to the customer. Fifth, completely failing to check the dependencies added to the project by external developers or agencies. The common thread in these mistakes is ignoring the license text for the sake of technical convenience; the legal consequences are often only noticed after product delivery, a funding round, or a warning notice.

When an open source license violation is detected, the first step is not to panic and erase history, but to determine the scope of the violation in a controlled manner. Which component was used, which version was used, under which license, whether it remained internal or was distributed to the customer, and whether the compatibility issue occurred at the file level or the entire product level – these must be quickly identified. Then, license texts, notice files, source code access mechanisms, distribution flow, and customer agreements should be examined together. If the issue is AGPL, whether there was network interference; if it's GPL, how the distribution was carried out; if it's MPL, which files were modified should be carefully evaluated. Collaboration between technical, legal, and product teams is essential at this stage.

The most effective preventative approach is for every company to have a written open-source compliance policy. This policy should specify which repositories code can be obtained from, the license approval process, dependency scanning, SBOM generation, the responsibilities of outsourced teams, which documents should be included during customer distribution, and who will make decisions in case of violations. For startups seeking investment, mergers and acquisitions, and companies selling software abroad, an open-source inventory is no longer a luxury but a necessity. This is because misuse of open-source code can lead not only to legal action but also to product recalls, distribution stoppages, customer loss, investor questions, and management liability. The duty of care in the Turkish Commercial Code and the organizational responsibility in the Turkish Code of Obligations legally support this corporate approach.

Conclusion

Open-source software is an indispensable part of the modern software development world; however, the term "open source" does not mean that legal risk is eliminated. On the contrary, the misuse of open-source licenses often leads to more complex consequences than the use of classic unlicensed software. This is because permission exists, but that permission is subject to specific conditions. When these conditions are violated, copyright infringement, breach of contract, damages, penalties, violations of the Personal Data Protection Law (KVKK), and the liability of company executives can all be combined in the same case. In Turkish law, computer programs are protected under the Copyright Law (FSEK); in case of infringement, the rights holder can claim up to three times the amount in compensation, as well as forfeiture and damages. The actions of employees within the company and external teams may also have separate consequences under the Turkish Code of Obligations (TBK) and the Turkish Commercial Code (TTK).

Therefore, the correct approach is this: Open source code should be managed not as "free code," but as a licensed intellectual property usage permit. Obtaining code without reading the license, distributing products without establishing license compliance, and leaving developer practices free from legal oversight create a serious vulnerability for any growing technology company. When used correctly, open source provides significant advantages; when used incorrectly, it can turn the most valuable part of the product into the subject of a legal dispute.

Frequently Asked Questions

Why does open-source software, even if free, pose a legal risk?
Because open source doesn't mean "unconditional free use." The OSI definition clearly states that open-source licenses are subject to specific distribution and usage terms.

Is it forbidden to use open-source code in a commercial product?
No. However, depending on which license is used, copyright notice, access to the source code, distribution under the same license, or notice obligations may arise. GPL, AGPL, MPL, and Apache do not all have the same effect.

Does infringing an open-source license directly constitute copyright infringement?
Each specific case is evaluated individually. However, exceeding the license terms can strengthen the claim that the use is now unauthorized and may raise claims under the Turkish Copyright Law.

If a developer makes a mistake at the company, is only the employee held responsible?
No. Under Articles 66 and 116 of the Turkish Code of Obligations, responsibility can also be discussed in relation to the employer and the debtor company. The company's selection, instruction, supervision, control, and organizational structure are important factors.

Can company executives be affected by open source license incompatibility?
Yes, they can. The duty of care under Article 369 of the Turkish Commercial Code and the liability for negligent breach under Article 553 can become problematic if a corporate compliance system is not established at all or if obvious risks are ignored.