The named pipes in qtsingleapp in Qt 5.x, as used in qBittorrent and SugarSync, are configured for remote access and allow remote attackers to cause a denial of service (application crash) via an unspecified string.

ownCloud Desktop Client before 2.0.1, when compiled with a Qt release after 5.3.x, does not call QNetworkReply::ignoreSslErrors with the list of errors to be ignored, which makes it easier for remote attackers to conduct man-in-the-middle (MITM) attacks by leveraging a server using a self-signed certificate. NOTE: this vulnerability exists because of a partial CVE-2015-4456 regression.

Multiple buffer overflows in gui/image/qgifhandler.cpp in the QtBase module in Qt before 4.8.7 and 5.x before 5.4.2 allow remote attackers to cause a denial of service (segmentation fault) and possibly execute arbitrary code via a crafted GIF image.

Multiple buffer overflows in gui/image/qbmphandler.cpp in the QtBase module in Qt before 4.8.7 and 5.x before 5.4.2 allow remote attackers to cause a denial of service (segmentation fault and crash) and possibly execute arbitrary code via a crafted BMP image.

Multiple buffer overflows in plugins/imageformats/ico/qicohandler.cpp in the QtBase module in Qt before 4.8.7 and 5.x before 5.4.2 allow remote attackers to cause a denial of service (segmentation fault and crash) and possibly execute arbitrary code via a crafted ICO image.