The PHP development team just released an update to the core PHP system. It’s a major stability and security enhancement to the 5.2.0 release. Everybody is strongly encouraged to upgrade to this release as soon as possible.

Quoted from the announcement:

Security Enhancements and Fixes in PHP 5.2.1:

  • Fixed possible safe_mode & open_basedir bypasses inside the session extension.
  • Prevent searchs engine from indexing the phpinfo() page.
  • Fixed a number of input processing bugs inside the filter extension.
  • Fixed unserialize() abuse on 64 bit systems with certain input strings.
  • Fixed possible overflows and stack corruptions in the session extension.
  • Fixed an underflow inside the internal sapi_header_op() function.
  • Fixed allocation bugs caused by attempts to allocate negative values in some code paths.
  • Fixed possible stack overflows inside zip, imap & sqlite extensions.
  • Fixed several possible buffer overflows inside the stream filters.
  • Fixed non-validated resource destruction inside the shmop extension.
  • Fixed a possible overflow in the str_replace() function.
  • Fixed possible clobbering of super-globals in several code paths.
  • Fixed a possible information disclosure inside the wddx extension.
  • Fixed a possible string format vulnerability in *print() functions on 64 bit systems.
  • Fixed a possible buffer overflow inside mail() and ibase_{delete,add,modify}_user() functions.
  • Fixed a string format vulnerability inside the odbc_result_all() function.
  • Memory limit is now enabled by default.
  • Added internal heap protection.
  • Extended filter extension support for $_SERVER in CGI and apache2 SAPIs.

The majority of the security vulnerabilities discovered and resolved can in most cases be only abused by local users and cannot be triggered remotely. However, some of the above issues can be triggered remotely in certain situations, or exploited by malicious local users on shared hosting setups utilizing PHP as an Apache module. Therefore, we strongly advise all users of PHP, regardless of the version to upgrade to 5.2.1 release as soon as possible. PHP 4.4.5 with equivalent security corrections will be available shortly.

The key improvements of PHP 5.2.1 include:

  • Several performance improvements in the engine, streams API and some Windows specific optimizations.
  • PDO_MySQL now uses buffered queries by default and emulates prepared statements to bypass limitations of MySQL’s prepared statement API.
  • Many improvements and enhancements to the filter and zip extensions.
  • Memory limit is now always enabled, this includes Windows builds, with a default limit of 128 megabytes.
  • Added several performance optimizations using faster Win32 APIs (this change means that PHP no longer supports Windows 98).
  • FastCGI speed optimized build of PHP for Windows made available for downloading.
  • Over 180 bug fixes.

For users upgrading from PHP 5.0 and PHP 5.1, an upgrade guide is available at, detailing the changes between those releases and PHP 5.2.1.

For a full list of changes in PHP 5.2.1, see the ChangeLog (

The new version compiled without any issue on my Intel Mac and worked like a charm. I do encountered some issues (I’m still working on it) on my production PPC Mac, but most of these occur because of stuff and libraries I’ve used in earlier setups. I wish I still had a second PPC Mac just to be able to clean up my production machine !