GKSu 2.0.2, when sudo-mode is not enabled, uses " (double quote) characters in a gksu-run-helper argument, which allows attackers to execute arbitrary commands in certain situations involving an untrusted substring within this argument, as demonstrated by an untrusted filename encountered during installation of a VirtualBox extension pack.
Gentoo Linux Security Advisory 201812-10 - A vulnerability in GKSu might allow attackers to execute arbitrary commands. Versions less than or equal to 2.0.2 are affected.