What are the legal consequences of violating an open-source license?

Violating an open-source license can result in legal action, financial penalties, and reputational harm. Open-source licenses are legally binding agreements, and failing to comply with their terms can lead to lawsuits, injunctions, or demands for corrective action. The specific consequences depend on the license type (e.g., MIT, GPL, Apache) and the jurisdiction, but common outcomes include being forced to release proprietary code, pay damages, or stop distributing the violating software.

For example, licenses like the GNU GPL require derivative works to be released under the same license. If a company uses GPL-licensed code in proprietary software without sharing the source, the copyright holder can sue. In 2008, the Free Software Foundation (FSF) settled a case against Cisco for distributing GPL-licensed code in its routers without complying with the license terms. Cisco had to release the modified source code and appoint an internal compliance officer. Similarly, violating permissive licenses like MIT or Apache—which mainly require attribution—could lead to demands for retroactive credit or financial compensation if the oversight harmed the original developer’s reputation or revenue.

Beyond direct legal risks, violations damage trust within the open-source community. Developers may avoid projects with a history of non-compliance, and companies might face public scrutiny. For instance, in 2021, the Software Freedom Conservancy audited several companies for GPL violations, leading to compliance fixes and public commitments to open-source norms. Even if a case doesn’t go to court, resolving violations often requires costly engineering effort to audit codebases, rewrite components, or negotiate settlements. Proactive compliance is far simpler than managing these repercussions after the fact.