This HTTP extension aims to provide a convenient and powerful set of functionality for one of PHPs major applications.
A buffer overflow can be triggered in the URL parsing functions of the PECL HTTP extension. This allows overflowing a buffer with data originating from an arbitrary HTTP request.
A remote attacker, through a specially crafted URI, could possibly execute arbitrary code with the privileges of the process.
There is no known workaround at this time.
All PECL HTTP users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-php/pecl-http-2.5.6"