The safe-level feature in Ruby 1.8.7 allows context-dependent attackers to modify strings via the NameError#to_s method when operating on Ruby objects. NOTE: this issue is due to an incomplete fix for CVE-2011-1005.
https://wiki.mageia.org/en/Support/Advisories/MGASA-2012-0294
https://bugzilla.redhat.com/show_bug.cgi?id=863484
http://www.openwall.com/lists/oss-security/2012/10/05/4
http://www.mandriva.com/security/advisories?name=MDVSA-2013:124