28.3: Open Source Maintainer Liability Protections¶

Disclaimer: This section provides general educational information about legal liability considerations for open source maintainers. It does not constitute legal advice. Maintainers with specific liability concerns should consult qualified legal counsel.

Open source maintainers occupy a peculiar position in the software ecosystem. They create software used by millions—sometimes billions—of users, embedded in critical infrastructure, financial systems, and life-safety applications. Yet most maintainers are unpaid volunteers working in their spare time, with no formal relationship to the organizations that depend on their work. When the xz-utils backdoor was discovered in March 2024, it highlighted not just security risks but the extraordinary responsibility placed on individual maintainers with minimal resources or support.

The growing regulatory focus on software security has intensified maintainer concerns about liability. Will maintainers face legal exposure when vulnerabilities in their software cause harm? Can hobby projects be held to the same standards as commercial software? These questions have generated significant anxiety in the open source community—and motivated advocacy for maintainer protections that recognize the unique nature of volunteer-driven open source development.

Current Maintainer Liability Exposure¶

The theoretical liability exposure for open source maintainers is broader than many realize, though actual litigation has been rare.

Potential liability theories:

• Negligence: Claims that maintainers failed to exercise reasonable care in development or vulnerability response
• Product liability: If courts extend product liability to software, maintainers could face strict liability for defects
• Misrepresentation: Claims based on security claims made in documentation or marketing
• Breach of contract: If license terms create enforceable obligations

Practical limiting factors:

Several factors have limited actual maintainer litigation:

• Damages and collectability: Individual maintainers typically lack assets making lawsuits economically worthwhile
• Causation complexity: Connecting maintainer conduct to specific harm through complex supply chains is difficult
• Public relations: Suing volunteer maintainers generates negative publicity
• Open source community norms: The community would react negatively to aggressive litigation

However, these practical protections are not legal protections. They may erode as software liability law evolves, as breaches cause increasingly significant harm, and as organizations seek recovery from available parties.

Known litigation:

Actual lawsuits against open source maintainers have been extremely rare. Most supply chain security litigation targets commercial entities—the organizations that incorporated open source components into products they sold. However, the absence of historical litigation provides limited comfort as the legal landscape shifts.

The EU CRA and similar regulations create new potential liability frameworks. Even if maintainers fall within carve-outs, the complexity of those carve-outs creates uncertainty that generates risk.

License Disclaimer Effectiveness¶

Open source licenses universally include warranty disclaimers and limitation of liability clauses. The MIT License, Apache License 2.0, GPL, and virtually all other open source licenses include language disclaiming warranties and limiting liability. These disclaimers provide significant but imperfect protection.

Disclaimer strengths:

• Courts generally enforce disclaimers in commercial contexts
• Clear, prominent disclaimer language increases enforceability
• Absence of payment strengthens the case for risk transfer to users
• User access to source code enables self-assessment of risks

Disclaimer limitations:

• Consumer protection laws may override disclaimers in some jurisdictions
• Disclaimers may not protect against gross negligence or intentional misconduct
• Some jurisdictions have mandatory warranty provisions that cannot be disclaimed
• Courts may find disclaimers unconscionable in contracts of adhesion

Jurisdictional variation:

Disclaimer effectiveness varies significantly by jurisdiction:

• United States: Generally enforces disclaimers between commercial parties; consumer transactions receive more scrutiny
• European Union: Consumer protection directives limit disclaimer effectiveness against consumers
• United Kingdom: Unfair Contract Terms Act 1977 imposes reasonableness requirements
• Australia: Australian Consumer Law creates non-excludable consumer guarantees

Maintainers distributing software globally face potential claims under any jurisdiction where their software is used—they cannot control which jurisdictions' laws may apply.

Foundation Membership as Liability Shield¶

Many open source projects operate under the umbrella of nonprofit foundations that provide legal structure and, importantly, liability protection for individual contributors.

How foundations protect maintainers:

• Corporate liability shield: The foundation, as a legal entity, assumes liability that would otherwise attach to individuals
• Insurance coverage: Foundations typically carry Directors & Officers (D&O) and general liability insurance
• Legal defense resources: Foundations can fund legal defense if litigation occurs
• Separation of personal assets: Individual maintainers' personal assets are protected by the corporate structure

Major open source foundations:

Foundation membership benefits:

Beyond liability protection, foundations provide:

• Fiscal sponsorship enabling project funding
• Trademark protection for project names
• Governance frameworks for decision-making
• Contributor license agreement management
• Legal review for licensing questions

Limitations of foundation protection:

Foundation membership doesn't provide unlimited protection:

• Individual misconduct may not be covered
• Activities outside foundation scope may lack protection
• Coverage limits on insurance cap potential recovery
• Foundations may face their own financial constraints

Not all projects can obtain foundation membership. Foundations have limited capacity and typically accept established projects with community governance. Individual maintainers of smaller projects may lack access to these protections.

EU CRA Open Source Provisions¶

The EU Cyber Resilience Act created significant concern in the open source community during its development. The CRA entered into force December 10, 2024, with main obligations applying from December 11, 2027. The final text includes carve-outs intended to protect non-commercial open source development while imposing obligations on commercial actors.

The non-commercial exclusion:

The CRA excludes from its scope "free and open-source software developed or supplied outside the course of a commercial activity." This exclusion protects:

• Hobby projects by individual developers
• Community-driven projects without commercial backing
• Software developed by volunteers not acting commercially
• Projects where monetary contributions only cover development costs

The exclusion does not protect:

• Open source developed as part of commercial activity
• Software that generates revenue for developers
• Projects backed by commercial entities
• Software marketed or sold commercially

The open source steward concept:

As discussed in Section 26.2, the CRA creates the "open source steward" category for foundations and similar organizations that support open source projects intended for commercial use. Stewards face reduced obligations:

• Establish cybersecurity policies for vulnerability handling
• Cooperate with market surveillance authorities
• Facilitate vulnerability reporting

Stewards are explicitly not subject to:

• Essential cybersecurity requirements
• Conformity assessment procedures
• CE marking obligations
• Full manufacturer liability

Commercial integrator responsibility:

The CRA places primary responsibility on commercial entities that integrate open source into products they sell. The manufacturer placing a product on the market—not the open source maintainer who created components—bears compliance obligations.

This architecture intentionally protects volunteer maintainers while ensuring commercial products meet security requirements. The commercial entity that profits from open source use assumes responsibility for ensuring that software meets CRA requirements.

Remaining concerns:

Despite carve-outs, concerns remain:

• The line between commercial and non-commercial can blur
• Steward obligations, while reduced, create new burdens for foundations
• Complexity of compliance may discourage foundation involvement
• Commercial entities may pressure maintainers for compliance assistance

The open source community continues monitoring CRA implementation to ensure carve-outs function as intended.

Advocacy for Maintainer Protections¶

The open source community has organized to advocate for maintainer protections as liability frameworks evolve.

Key advocacy efforts:

OpenSSF and Linux Foundation have engaged extensively with policymakers on software security regulations, advocating for provisions that recognize open source development's unique characteristics.

European Commission engagement: Multiple foundations submitted comments during CRA development, resulting in the open source steward concept and refined exclusion language.

U.S. policy engagement: Foundations have engaged with CISA and the White House on secure software development initiatives, emphasizing voluntary approaches over mandates for open source.

Open Source Initiative (OSI) and Free Software Foundation Europe (FSFE): These organizations have advocated for maintainer protections in regulatory proceedings.

Advocacy themes:

Common advocacy positions include:

• Distinguishing volunteer open source from commercial software
• Placing compliance obligations on commercial integrators
• Providing safe harbors for following security best practices
• Funding security improvements rather than imposing unfunded mandates
• Recognizing that individual maintainers cannot be held to enterprise standards

Policy wins:

Advocacy has achieved meaningful results:

• EU CRA open source carve-outs
• Recognition of open source in CISA Secure by Design principles
• Government investment in open source security through OpenSSF
• Increased dialog between regulators and open source community

Continued advocacy remains essential as additional regulations develop globally.

Practical Risk Mitigation for Maintainers¶

While legal protections remain imperfect, maintainers can take practical steps to reduce liability exposure.

Documentation and disclaimers:

• Include clear warranty disclaimers in LICENSE files
• Document security limitations in README or SECURITY.md
• Avoid making security claims you cannot substantiate
• Clearly state project status (experimental, production, deprecated)

Security practices:

• Establish a security policy (SECURITY.md) with reporting instructions
• Respond promptly and professionally to vulnerability reports
• Document vulnerability handling processes
• Maintain records of security-related decisions

Governance clarity:

• Clarify project governance and decision-making processes
• Document maintainer roles and responsibilities
• Establish clear contribution processes
• Use Contributor License Agreements or Developer Certificate of Origin consistently

Foundation membership:

• Consider joining a fiscal sponsor or foundation if eligible
• Software Freedom Conservancy accepts individual projects
• NumFOCUS supports scientific computing projects
• Open Collective provides fiscal sponsorship for various projects

Limiting exposure:

• Consider appropriate scope for your project
• Avoid taking on security-critical functionality you cannot maintain
• Be honest about maintenance capacity and limitations
• Consider graceful deprecation if you cannot continue maintaining

Insurance and Support Resources¶

Insurance options:

Insurance specifically for open source maintainers remains limited, but options exist:

• Foundation coverage: Projects under foundation umbrellas typically benefit from foundation insurance
• Professional liability insurance: Maintainers doing consulting may have coverage extending to open source work
• Umbrella liability policies: Personal umbrella policies may provide some protection
• Fiscal sponsor insurance: Some fiscal sponsors include liability coverage

The Open Source Collective and similar organizations are exploring group insurance options for maintainers, though comprehensive solutions remain elusive.

Legal support resources:

• Software Freedom Law Center: Provides legal services to open source projects
• Electronic Frontier Foundation: Offers legal support for digital rights issues
• Open Source Initiative: Provides licensing guidance and advocacy
• Foundation legal programs: Apache, Eclipse, and other foundations offer legal support to member projects

Community resources:

• OpenSSF Alpha-Omega: Provides security resources to critical projects
• Tidelift: Offers paid support arrangements that include legal indemnification
• GitHub Sponsors and Open Collective: Enable financial support for maintainers

Recommendations¶

We recommend maintainers take the following steps to manage liability risk:

1. Include prominent disclaimers in license files and documentation, clearly stating software is provided without warranty

2. Document your project's status honestly—experimental, beta, or production-ready—and avoid overstating security capabilities

3. Establish security reporting processes through SECURITY.md, demonstrating good faith vulnerability handling

4. Consider foundation membership for established projects, gaining corporate liability protection

5. Maintain records of security decisions and vulnerability responses in case they become relevant

6. Engage with advocacy efforts through organizations like OpenSSF that represent maintainer interests

7. Know your limits and communicate them clearly—if you cannot maintain security-critical functionality, say so

8. Seek legal counsel if you receive threats or believe you face specific liability exposure

The open source community has successfully advocated for maintainer protections, but vigilance remains necessary as software liability evolves. Maintainers who document their practices, participate in community governance, and engage with advocacy efforts contribute to protecting both themselves and the broader ecosystem.