Pierre-Alain Joye has posted about the release of the latest version of his Zip PECL extension - version 1.8.7 - including what it fixes.
Zip-1.8.7 fixes two problems related to open_basedir and safe mode. One was discovered by Stefan Esser (#20 in his mopb) and affects the zip:// stream wrapper. The other is in the open method of the ZipArchive class. I I forgot these two places while applying the php6+ changes and cleaning the code base. I recommend to upgrade as soon as possible.
He notes that, thanks to information from Stefan Esser, this issue was fixed the same day it was posted (the zip:// flaw he mentioned). You can get more information on this package from its PECL homepage or just grab the latest update here.