The QSharedMemory class in Qt 5.0.0, 4.8.x before 4.8.5, 4.7.x before 4.7.6, and other versions including 4.4.0 uses weak permissions (world-readable and world-writable) for shared memory segments, which allows local users to read sensitive information or modify critical program data, as demonstrated by reading a pixmap being sent to an X server.

Heap-based buffer overflow in the Lookup_MarkMarkPos function in the HarfBuzz module (harfbuzz-gpos.c), as used by Qt before 4.7.4 and Pango, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted font file.

Integer overflow in Qt 3.3 before 3.3.7, 4.1 before 4.1.5, and 4.2 before 4.2.1, as used in the KDE khtml library, kdelibs 3.1.3, and possibly other packages, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted pixmap image.