PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML.
Several vulnerabilities were discovered on PHP4 and PHP5 by Infigo, Tonu Samuel and Maksymilian Arciemowicz. These included a buffer overflow in the wordwrap() function, restriction bypasses in the copy() and tempname() functions, a cross-site scripting issue in the phpinfo() function, a potential crash in the substr_compare() function and a memory leak in the non-binary-safe html_entity_decode() function.
Remote attackers might be able to exploit these issues in PHP applications making use of the affected functions, potentially resulting in the execution of arbitrary code, Denial of Service, execution of scripted contents in the context of the affected site, security bypass or information leak.
There is no known workaround at this point.
All PHP users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose dev-lang/php