PHP 5.1.0. Release Announcement
The PHP development team is proud to announce the release of PHP PHP 5.1.0.
Some of the key features of PHP 5.1.0 include:
- A complete rewrite of date handling code, with improved timezone support.
- Significant performance improvements compared to PHP 5.0.X.
- PDO extension is now enabled by default.
- Over 30 new functions in various extensions and built-in functionality.
- Bundled libraries, PCRE and SQLite upgraded to latest versions.
- Over 400 various bug fixes.
- PEAR upgraded to version 1.4.5
 For a full list of changes in PHP 5.1.0, see the
 ChangeLog.
In addition to new features, this release includes a number of important security fixes:
- Fixed a Cross Site Scripting (XSS)
	vulnerability in phpinfo() that could
	lead f.e. to cookie exposure, when a phpinfo() script is accidently left
	on a production server.
- Fixed multiple safe_mode/open_basedir bypass vulnerabilities in ext/curl
	and ext/gd that could lead to exposure of files normally not accessible due
	to safe_mode or open_basedir restrictions.
- Fixed a possible $GLOBALS overwrite problem in file upload handling,
	extract() and import_request_variables() that could lead to unexpected
	security holes in scripts assumed secure. (For more information, see here).
- Fixed a problem when a request was terminated due to memory_limit
	constraints during certain
	parse_str() calls. In some cases
	this can result in register_globals being turned on.
- Fixed an issue with trailing slashes in allowed basedirs. They were ignored
	by open_basedir checks, so that specified basedirs were handled as prefixes
	and not as full directory names.
- Fixed an issue with calling virtual()
	on Apache 2. This allowed bypassing of certain configuration directives
	like safe_mode or open_basedir.
- Updated to the latest pcrelib to fix a possible integer overflow
	vulnerability announced in CAN-2005-2491.
- Possible header injection in mb_send_mail() function via the "To" address, the first parameter of the function.
All users of PHP 5.0 and early adopters of 5.1 betas are strongly advised to upgrade to 5.1 as soon as
possible. Furthermore, 5.1 branch obsoletes the 5.0 PHP branch.
Upgrading Guide is available to ease the transition from prior PHP versions.