Summary Under the proposed Cloud and AI Development Act (CADA), the share-and-reuse rule is set out in Article 42. As proposed, when a Union entity or public sector body makes software it holds intellectual property rights in available for reuse under an open source licence, it must do so through a catalogue or repository that is connected to, and accessible through, the EU Open Source Solutions Catalogue (EU OSS Catalogue). The rule does not require any body to open-source its software; it governs how software is published if the body chooses to make it available for reuse, so that publicly developed code is discoverable across the EU public sector. CADA is still a proposal, so this is not yet in force.

Detail

CADA (COM(2026) 502 final) is a Commission proposal that promotes open source as one lever for the EU's technological autonomy. Within the open source chapter (Chapter V of Title IV), Article 42 addresses the sharing and reuse of software developed by or for public authorities.

The core rule: Article 42

The provision, headed "Share and reuse of software," reads as proposed:

"When making software to which they hold intellectual property rights available for reuse under an open source licence, a Union entity or public sector body shall do so using a catalogue or repository that is connected to, and made accessible through, the EU OSS Catalogue referred to in Article 43."

The rule is conditional. It is triggered only when a public body chooses to make software available for reuse under an open source licence and holds the IP rights in that software. It does not compel any body to release software, and it does not impose its own standalone repository. What it requires is the channel: any such software must be published through a catalogue or repository that is technically connected to the central EU OSS Catalogue.

Why this rule exists: Recital 83

The rationale is set out in Recital 83 of the proposal. It notes that "an increasing number of Union entities and public-sector bodies are sharing software developed by or for them and making it available for reuse under an open-source licence," which "may be considered to be in the public interest and may maximise the value of public expenditure, reduce duplication costs and foster innovation across the Union." But, it continues, software "is often made available and accessible in different repositories or catalogues, hampering searchability, discoverability and, ultimately, reuse." It is therefore "necessary to require Union entities and public-sector bodies that voluntarily decide to make software available for reuse to do so in a catalogue or repository that is connected to" the EU OSS Catalogue.

By requiring connection to a central catalogue, the proposal aims to:

  1. Maximise public value — keep publicly funded software from being lost in disconnected repositories;
  2. Reduce duplication — let other public bodies find and reuse existing solutions; and
  3. Foster reuse and innovation — create a single place to search for reusable public-sector software.

The central hub: the EU OSS Catalogue (Article 43)

Article 42 works with Article 43, which establishes the EU Open Source Solutions Catalogue. Under Article 43, the Commission would provide and maintain the EU OSS Catalogue as a centralised catalogue to access software made available for reuse by Union entities and public sector bodies. It would be hosted on the Interoperable Europe portal referred to in Article 8 of Regulation (EU) 2024/903 and be accessible electronically free of charge. Under Article 43(3), the Commission would decide, "on the basis of objective and relevant criteria," on requests from any Union entity or public sector body owning or maintaining a catalogue or repository to have it connected to and made accessible through the EU OSS Catalogue.

In other words, a national or local open-source portal can serve as the interface for its public bodies, provided it is connected to the EU-wide catalogue.

Scope and triggers

The Article 42 obligation arises where all of the following hold:

  1. The body is a Union entity or a public sector body (in CADA, "public sector body" takes the meaning given in Directive (EU) 2019/1024, the Open Data Directive);
  2. The body holds the intellectual property rights in the software;
  3. The body decides to make that software available for reuse; and
  4. Reuse is under an open source licence (a defined term in CADA, drawn from the Interoperable Europe Act).

Where a body uses third-party proprietary software, or open-source software it does not own, this particular rule is not engaged in the same way. The broader "open source first" preference in Article 41 still encourages the use of open standards and components generally — but, again, as an encouragement rather than a hard mandate.

What this means for you

For public-sector IT managers, procurement officers and legal counsel, the share-and-reuse rule — if adopted — would add steps to software lifecycle management.

1. Know which assets are in scope

Identify software your organisation develops in-house or commissions where you retain the IP rights and might release for reuse. Note where any already-released tools are hosted — disconnected GitHub accounts, intranets, or unlinked national portals would need a plan to connect.

2. Choose a connected repository

You would not necessarily upload code to a Commission server. You could use a national or regional open-source catalogue, provided it is connected to the EU OSS Catalogue. When tendering for software development, you can require that any open-sourced deliverables be publishable in a connected repository.

3. Update procurement specifications

For new software development, you can state that code for which the authority holds IP rights, if open-sourced, must be released under an open source licence and published via a catalogue connected to the EU OSS Catalogue — avoiding a later retrofit.

4. Use the catalogue as a source, not just a destination

As the catalogue grows it becomes a place to find vetted, reusable components. Building a "catalogue check" into procurement supports the wider reuse and total-cost goals of the open source chapter.

5. Coordinate with national authorities

Because the Commission would set the criteria for connecting catalogues (Article 43(3)), stay engaged with your national digital agency, which will likely define the technical standards for how local repositories feed into the EU system.

These are proposed obligations; CADA must be adopted and apply before they take effect.

Common misconceptions

Misconception 1: "We must open-source all our software." No. Article 42 applies only when a body decides to make software available for reuse, and only to software it owns. CADA does not require all public-sector software to be open-sourced. Article 41 encourages open source use and reuse, but as an encouragement.

Misconception 2: "We can publish on any private account." If software owned by a public sector body is released for reuse, Article 42 requires it to be in a catalogue or repository connected to the EU OSS Catalogue. The aim is institutional discoverability, not mere public visibility on an unaffiliated account.

Misconception 3: "This applies retroactively to all our existing code." The rule governs how software is published when a body makes it available for reuse. CADA does not, on its face, retroactively force existing software into the catalogue; the obligation attaches to the act of making software available for reuse under an open source licence.

Misconception 4: "The EU OSS Catalogue replaces national portals." Not necessarily. National or regional portals can remain the local interface, provided they are connected to the EU OSS Catalogue under Article 43(3). The EU catalogue acts as a central, federated access point.

Related

This is general information about a draft EU regulation, not legal advice.