A heap buffer overflow (out-of-bounds READ) exists in decoder_context::decode_slice_unit_WPP() in libde265/decctx.cc. When decoding a WPP (Wavefront Parallel Processing) HEVC slice, ctbAddrRS is computed as ctbRow * ctbsWidth inside the entry-point loop. If the PPS/SPS headers are crafted so that this value exceeds pps.CtbAddrRStoTS.size(), the subsequent array access pps.CtbAddrRStoTS[ctbAddrRS] reads past the end of the allocated vector, triggering a heap-buffer-overflow confirmed by AddressSanitizer.