An issue was discovered in KDE Plasma Workspace before 5.12.0. dataengines/notifications/notificationsengine.cpp allows remote attackers to discover client IP addresses via a URL in a notification, as demonstrated by the src attribute of an IMG element.
https://www.kde.org/announcements/plasma-5.11.5-5.12.0-changelog.php
https://phabricator.kde.org/D10188
https://cgit.kde.org/plasma-workspace.git/commit/?id=8164beac15ea34ec0d1564f0557fe3e742bdd938
https://cgit.kde.org/plasma-workspace.git/commit/?id=5bc696b5abcdb460c1017592e80b2d7f6ed3107c