Article 48 Vienna Convention on the Law of Treaties

Error

1. A State may invoke an error in a treaty as invalidating its consent to be bound by the treaty if the error relates to a fact or situation which was assumed by that State to exist at the time when the treaty was concluded and formed an essential basis of its consent to be bound by the treaty.

2. Paragraph 1 shall not apply if the State in question contributed by its own conduct to the error
or if the circumstances were such as to put that State on notice of a possible error.

3. An error relating only to the wording of the text of a treaty does not affect its validity; article 79 then applies.

See also: Article 47 Vienna Convention on the Law of Treaties