Heap-based buffer overflow in the pango_ft2_font_render_box_glyph 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 via a crafted font file, related to the glyph box for an FT_Bitmap object.