How can I tell whether a Creative Commons licence is valid?

A Creative Commons license is valid when the license version and conditions are correctly stated, the licensor has authority to apply it, the work is properly marked, and the license link resolves to the official deed. You cannot get total certainty, but you can run a four-step check: verify the source, record the evidence, confirm your planned use complies, and attribute correctly. If any part is missing or broken, treat the license as unreliable and do not use the work.

Start at the Original Source

Open the page where the rightsholder or authorised uploader published the work. Do not trust a repost on a third-party site, a search thumbnail, or a platform filter that says CC. Look for a clear notice that identifies the work and the rightsholder, names the exact license and version (CC BY 4.0, not just CC BY), and provides a link to the license deed or legal code. The current suite has six 4.0 International licenses, all requiring attribution. If the notice omits the version number or links to a page that is not the official deed on creativecommons.org, the license is not reliable.

Check the Licensor

Only the copyright holder or someone with express authority may apply a CC license. If a platform user who is not the original rightsholder uploads the work and slaps a CC badge, they may not own the rights. Joint authors, employment ownership, commissioned work terms, performer rights, samples and third-party inclusions all affect who controls the rights. You cannot verify ownership from the license notice alone. If the work looks like a professional photograph but the source is a random forum, the license claim is suspect. Contact the identified rightsholder through a verifiable channel and ask for confirmation.

Run through this checklist before using any CC-licensed work. It covers the four actions that separate a valid reuse from a license breach.

Verify

Open the original source page. Record the exact license and version from that page, not from a summary. Check that the license link goes to the official deed or legal code at creativecommons.org. For 4.0, the legal code URL is the deed URL plus legalcode. If the link is broken or redirects to a general page, the license notice is not reliable. Also check whether the notice excludes any material: third-party content, samples, or embedded clips. The license only covers what the notice explicitly includes.

Record

Save a copy of the source page, the license notice, the rightsholder name, the source URL, the exact license and version, any exclusions, and the date you checked. Take a screenshot if the use matters to you. This record is your proof that the license was present when you accessed the work. If a dispute arises later, you need that evidence because the licensor may change the page or remove the license. Creative Commons does not register works and does not verify ownership; the record is your own responsibility.

Comply

Identify what you plan to do with the work: share unchanged, adapt, use commercially, or combine with other material. Test each condition against that plan. Under an ND license, you cannot share adapted material. Under an NC license, your use must not be primarily intended for commercial advantage or monetary compensation; the identity of your organisation does not decide it. Under SA, if you share an adaptation, you must apply the same license or one officially named compatible. Version 4.0 lists one-way compatibility from BY-SA 4.0 to GPLv3 for adapted material; do not assume other SA licenses are compatible. If your planned use carries material commercial risk, get separate permission or local legal advice.

Attribute

Under 4.0, a reuser must retain, when supplied by the licensor: identification of the rightsholder and designated attribution parties; a copyright notice; a notice referring to the license; a warranty disclaimer; and a URI or hyperlink to the material where reasonably practicable. The reuser must link or refer to the license and indicate modifications, retaining earlier modification notices. Attribution may be done in any reasonable manner for the medium. The TASL mnemonic (title, author, source, license) is useful but is not the complete legal text. For 4.0, add an indication of changes and preserve supplied notices. Do not imply endorsement. A consolidated credits page can be reasonable for many works if the mapping is clear and the credits remain readily accessible.

Missing or Broken Links

A common failure is a missing or broken license link. If the notice says CC BY 4.0 but the link goes to a dead page or a generic search result, the license is not reliably applied. The official deed must resolve. Another common failure is a missing version number. A notice that says only CC BY without a version is incomplete; you cannot confirm which terms apply because the rules changed between versions. Version 4.0 does not have a ported variant, but older versions do, and a port from a different jurisdiction may not apply to your location. Before 4.0, Creative Commons published jurisdiction-specific ports; 4.0 is an international license designed without ports. If the notice uses a ported variant for a jurisdiction that is not the work's origin, treat the license as suspect.

Platform Conflicts

Some platforms let users select a CC option in their upload interface, but the platform's current terms may conflict with the license. Version 4.0 prohibits a recipient from imposing additional legal terms or effective technological measures that restrict another recipient's exercise of the licensed rights. If the platform requires exclusive sublicensing, download restrictions, or DRM, the license may be compromised. Check the platform's current help page instead of assuming a CC badge resolves the conflict.

The Decisive Exception

A license is invalid if the licensor did not control the rights. No amount of correct formatting fixes that. You cannot tell from the notice alone whether the uploader owned the rights. If the work contains samples, third-party content, or material that looks like a famous brand, the license may not cover those parts. When you doubt the license, find a different work from a verifiable source.