The installer in PEAR 1.9.2 and earlier allows local users to overwrite arbitrary files via a symlink attack on the package.xml file, related to the (1) download_dir, (2) cache_dir, (3) tmp_dir, and (4) pear-build-download directories. NOTE: this vulnerability exists because of an incomplete fix for CVE-2011-1072.
http://openwall.com/lists/oss-security/2011/02/28/5
http://openwall.com/lists/oss-security/2011/03/01/4
http://openwall.com/lists/oss-security/2011/03/01/5
http://openwall.com/lists/oss-security/2011/03/01/7
http://openwall.com/lists/oss-security/2011/03/01/8
http://openwall.com/lists/oss-security/2011/03/01/9