lightdm before 0.9.6 writes in .dmrc and Xauthority files using root permissions while the files are in user controlled folders. A local user can overwrite root-owned files via a symlink, which can allow possible privilege escalation.
[
{
"product": "lightdm",
"vendor": "lightdm",
"versions": [
{
"status": "affected",
"version": "before 0.9.6"
}
]
}
]