An issue was discovered in Qt through 5.12.9, and 5.13.x through 5.15.x before 5.15.1. read_xbm_body in gui/image/qxbmhandler.cpp has a buffer over-read.
https://security.gentoo.org/glsa/202009-04
https://lists.debian.org/debian-lts-announce/2020/09/msg00024.html
https://lists.debian.org/debian-lts-announce/2020/09/msg00023.html
https://codereview.qt-project.org/c/qt/qtbase/+/308496