gtk-vnc before 0.7.0 does not properly check boundaries of subrectangle-containing tiles, which allows remote servers to execute arbitrary code via the src x, y coordinates in a crafted (1) rre, (2) hextile, or (3) copyrect tile.
"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2017-5884.json"