Gitk is a Tcl/Tk based Git history browser. Starting with 1.7.0, when a user clones an untrusted repository and runs gitk without additional command arguments, files for which the user has write permission can be created and truncated. The option Support per-file encoding must have been enabled before in Gitk's Preferences. This option is disabled by default. The same happens when Show origin of this line is used in the main window (regardless of whether Support per-file encoding is enabled or not). This vulnerability is fixed in 2.43.7, 2.44.4, 2.45.4, 2.46.4, 2.47.3, 2.48.2, 2.49.1, and 2.50.1.
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.