Gentoo Linux Security Advisory GLSA 200711-13 – 3proxy contains a double free vulnerability in the ftpprchild() function, which frees param->hostname and calls the parsehostname() function, which in turn attempts to free param->hostname again. Versions less than 0.5.3j are affected.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/60796/glsa-200711-13.txt
Source: https://packetstormsecurity.com/files/60796/Gentoo-Linux-Security-Advisory-200711-13.html