* Eight exchanges affected by tech glitch
* Deutsche Boerse says it is software issue
* Xetra open after nearly three hours of outage (Updates with Deutsche Boerse on glitch details)
By Thyagaraju Adinarayan
LONDON, July 1 (Reuters) - The reappearance of a software glitch that was first seen in April was behind a nearly three hour outage on Wednesday on Germany's electronic trading platform Xetra, the exchange operator Deutsche Boerse DB1Gn.DE said.
The issue resulted from a problem with third-party software and has been fixed, Deutsche Boerse said.
"The system is now running stably and we expect it to remain so," Deutsche Boerse said on Wednesday.
The technical snag on Wednesday follows one of the exchange operator's longest outages in April when the Frankfurt stock market was halted for more than four hours. Executive Theodor Weimer said after the April blackout that the stock exchange had taken precautions to avoid such a breakdown in the future.
The interruption in the fully-electronic cash market trading system affected stock exchanges in Frankfurt, Vienna, Ljubljana, Prague, Budapest, Zagreb, Malta and Sofia as they use the Xetra T7 system.
The exchanges came back online around 0930 GMT.
The German stock exchange's cash markets generated a turnover of 159.8 billion euros ($179.5 billion) in May.
Some European bond and stocks futures affected by the Xetra issue have also resumed trading. ($1 = 0.8905 euros)