ext/common/ServerInstanceDir.h in Phusion Passenger gem before 4.0.6 for Ruby allows local users to gain privileges or possibly change the ownership of arbitrary directories via a symlink attack on a directory with a predictable name in /tmp/.

References

• https://nvd.nist.gov/vuln/detail/CVE-2013-4136
• phusion/passenger@5483b32
• https://code.google.com/p/phusion-passenger/issues/detail?id=910
• GHSA-w6rc-q387-vpgq
• https://github.com/phusion/passenger/blob/release-4.0.6/NEWS
• http://rhn.redhat.com/errata/RHSA-2013-1136.html
• http://www.openwall.com/lists/oss-security/2013/07/16/6
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/passenger/CVE-2013-4136.yml