pango: Heap-based buffer overflow by rendering glyph box for certain FT_Bitmap objects

Heap-based buffer overflow in the pangoft2fontrenderboxglyph function in pango/pangoft2-render.c in libpango in Pango 1.28.3 and earlier, when the FreeType2 backend is enabled, allows user-assisted remote attackers to cause a denial of service application crash or possibly execute arbitrary code...