Samsung could be forced to stop selling some phones after Apple won an appeal in a US court.
The decision comes after a lawsuit first filed in 2012 in which Apple claimed Samsung was using some of its technology without proper permission.
That case was decided in May 2014 when Apple was awarded $120m (£76m) damages.
Apple appealed, saying Samsung should stop selling phones using the disputed features. Judges disagreed but this latest ruling overturns that decision.
Apple’s bid to stop Samsung selling some handsets was initially denied because the judges overseeing the case said the company had not demonstrated it had suffered significant harm from the infringement.
Now, two of the three judges reviewing the case have said Apple deserves an injunction to stop Samsung selling some phones.
However, this does not mean that Samsung will be forced to stop selling phones that use the disputed technology. The ruling means the case returns to the lower district court which will decide on whether an injunction is appropriate.
It is not clear what impact the ruling will have on Samsung because it only covers phones, such as the Galaxy S3, that were sold in 2012 and have now largely disappeared from shop shelves. In addition, Samsung has updated the software on its handsets so newer models do not use the disputed features.
“Apple has won every round,” Prof Michael Risch from the Villanova University School of Law told Reuters. “But the reality is it hasn’t actually slowed Samsung down.”
Samsung said the decision would not stop it selling its flagship handsets and added that the decision was “unfounded”.
“We will pursue our rights to have the full Court of Appeal review today’s decision,” it said in a statement.
For its part, Apple repeated a statement it made early in the case in which it accused Samsung of “wilfully” stealing its technology.
At issue were Apple patents covering autocorrect software, sliding a finger on a screen to unlock a phone and ways to turn text into hyperlinks.
Apple and Samsung have faced each other in court many times over technology patents they own. In late 2014, the two firms agreed to drop all the patent cases being fought outside the US.
Still at issue is a 2012 decision in a separate case that initially awarded Apple more than $1bn in damages for Samsung’s use of its patented technologies.
Subsequent legal hearings reduced the damages to $930m but Samsung has appealed against this revised figure. BBC