Multiple stack-based buffer overflows in pdf_shade4.c in MuPDF before commit 20091125231942 as used in SumatraPDF before 1.0.1 allow remote attackers to cause a denial of service and possibly execute arbitrary code via a /Decode array for certain types of shading that are not properly handled by the (1) pdf_loadtype4shade (2) pdf_loadtype5shade (3) pdf_loadtype6shade and (4) pdf_loadtype7shade functions. NOTE: some of these details are obtained from third party information.