Improper Neutralization of Special Elements used in a Command ('Command Injection')
The fetch_url function in usr.bin/ftp/fetch.c in tnftp, as used in NetBSD 5.1 through 5.1.4, 5.2 through 5.2.2, 6.0 through 6.0.6, and 6.1 through 6.1.5 allows remote attackers to execute arbitrary commands via a | (pipe) character at the end of an HTTP redirect.
CWE-77 - Command Injection
A command injection attack involves injecting an operating system command through the data input, which gets executed on the host operating system with the privileges of the victimized application. The impact of a command injection attack may range from loss of data confidentiality and integrity to unauthorized remote access to the hosting system. The attack may cause serious data breaches and system takeover.