Can the cracks found on the A380 wings tear the wing apart?
The issue has been fixed, for both the old and new A380's. Before the fix, the first 120 A380's did not face any danger according to Airbus.
From begadistrictnews.com.au:

&quot;The aircraft is absolutely safe because there are so many ways for the loads to travel within the structure of the wing,&quot; [Airbus's head of engineering, Charles Champion] said.
&quot;As it really is not a safety issue, we will inspect them over time ... within the next four years – some of them before.&quot;

From Wikipedia:

High-strength aluminum (type 7449) reinforced with carbon fiber was used in the wing brackets of the first 120 A380s to reduce weight, but cracks have been discovered and new sets of the more critical brackets will be made of standard aluminum 7010, increasing weight by 90 kg (198 lb).

From aviationweek.com:

Airbus has developed two fixes it says will permanently deal with the cracking of some rib-feet, which has already resulted in an airworthiness directive requiring enhanced inspection intervals and fixes where component cracking is found. One solution addresses the retrofit fix while the other alters the production process so the problem never occurs. The fixes should restore the aircraft to 19,000 flight cycles and regular inspection intervals, says [Tom Williams, Airbus’s executive VP-programs].

From flightglobal.com:

[21 March, 2014] LHT and Ameco to complete A380 wing-rib fixes next year.


Related: How strong is the A380 fuselage-wing joint?