The Phar extension for PHP does not properly handle crafted tar files, leading to a heap-based buffer overflow. PHP applications processing tar files could crash or, potentially, execute arbitrary code.
In addition, this update addresses a regression which caused a crash when accessing a global object that is returned as $this from __get.
For the stable distribution (squeeze), this problem has been fixed in version 5.3.3-7+squeeze13.
For the testing distribution (wheezy) and the unstable distribution (sid), this problem has been fixed in version 5.4.4~rc1-1.
We recommend that you upgrade your php5 packages.