PyGIT.py in the Trac Git plugin (trac-git) before 0.0.20080710-3+lenny1 and before 0.0.20090320-1 on Debian GNU/Linux, when enabled in Trac, allows remote attackers to execute arbitrary commands via shell metacharacters in a crafted HTTP query that is used to generate a certain git command.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.