To report security bugs, and to view a list of releases with security fixes, please see https://gnome.pages.gitlab.gnome.org/librsvg/devel-docs/security.html which is part of the development guide for librsvg.

The source for that page is at https://gitlab.gnome.org/GNOME/librsvg/-/blob/main/devel-docs/security.rst which is the devel-docs/security.rst in this repository.