Permissions, Privileges, and Access Controls
The safe-level feature in Ruby 1.8.6 through 1.8.6-420, 1.8.7 through 1.8.7-330, and 1.8.8dev allows context-dependent attackers to modify strings via the Exception#to_s method, as demonstrated by changing an intended pathname.
CWE-264 - Permissions Privileges and Access Controls
CWE 264 (permissions, privileges, and access controls) is not a weakness in and of itself, rather it is a category of weaknesses related to the management of permissions, privileges, and other security features used to perform access control. If not addressed, the weaknesses in this category allow attackers to gain privileges for an unintended sphere of control, access sensitive information, and execute arbitrary commands.