rack/file.rb (Rack::File) in Rack 1.5.x before 1.5.2 and 1.4.x before 1.4.5 allows attackers to access arbitrary files outside the intended root directory via a crafted PATH_INFO environment variable, probably a directory traversal vulnerability that is remotely exploitable, aka "symlink path traversals."
Vector
NETWORK
Complexity
MEDIUM
Authentication
NONE
Confidentiality
PARTIAL
Integrity
NONE
Availability
NONE
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (ID 22)
Related CAPEC 7
Relative Path Traversal (CAPEC-ID 139)
Directory Traversal (CAPEC-ID 213)
File System Function Injection, Content Based (CAPEC-ID 23)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (CAPEC-ID 64)
Manipulating Input to File System Calls (CAPEC-ID 76)
Using Escaped Slashes in Alternate Encoding (CAPEC-ID 78)
Using Slashes in Alternate Encoding (CAPEC-ID 79)