bookserver in KDE Arianna before 26.04.1 allows attackers to read files over a socket connection by guessing a URL.
https://kde.org/info/security/advisory-20260424-1.txt
https://invent.kde.org/graphics/arianna/-/commit/485851d25de279a9d2711d3780443530e9851300
https://invent.kde.org/graphics/arianna/-/commit/3cd56fce103ab62887c5592827d78a1197cd926a