A flaw was found in Apache Commons Text packages 1.5 through 1.9. The affected versions allow an attacker to benefit from a variable interpolation process contained in Apache Commons Text, which can cause properties to be dynamically defined. Server applications are vulnerable to remote code execution (RCE) and unintentional contact with untrusted remote servers.

Summary

A Path Traversal vulnerability exists when using non-default configuration options UPLOADDIR and UPLOADKEEPFILENAME=True. An attacker can write uploaded files to arbitrary locations on the filesystem by crafting a malicious filename.

Details

When UPLOADDIR is set and UPLOADKEEPFILENAME is True, the library constructs the file path using os.path.join(filedir, fname). Due to the behavior of os.path.join(), if the filename begins with a /, all preceding path components are discarded:

py os.path.join("/upload/dir", "/etc/malicious") == "/etc/malicious" This allows an attacker to bypass the intended upload directory and write files to arbitrary paths. Affected Configuration Projects are only affected if all of the following are true: - UPLOADDIR is set - UPLOADKEEPFILENAME is set to True - The uploaded file exceeds MAXMEMORYFILESIZE (triggering a flush to disk)

The default configuration is not vulnerable. Impact Arbitrary file write to attacker-controlled paths on the filesystem. Mitigation Upgrade to version 0.0.22, or avoid using UPLOADKEEPFILENAME=True in project configurations.