Thread:Project talk:Support desk/Fatal error: Possible integer overflow in memory allocation/reply (14)

It's not a MediaWiki bug, but a problem with either PHP or a hardware problem. The fact that it didn't happened in previous versions is because the new version is able to trigger that bug somewhat, but the bug is in the PHP engine, apache or somewhere else.

Looking for that error in search engines gives me a lot of results for other PHP software like joomla, phpBB, etc.

The only solution would be to get a new version of PHP, or even recompile PHP yourself, to see if that solves your problem, although some of the reports I've seen are from old PHP versions from 2006(!) so it may not solve the problem at all.