Mapserver 5.2, 5.4 and 5.6 before 5.6.5-2 improperly validates symbol index values during Mapfile parsing.
https://trac.osgeo.org/mapserver/ticket/3641
https://security-tracker.debian.org/tracker/CVE-2010-1678
https://people.canonical.com/~ubuntu-security/cve/2010/CVE-2010-1678.html