| diff --git a/third_party/libopenjpeg/j2k.c b/third_party/libopenjpeg/j2k.c | 
 | index 8e343ab2e..5e1494394 100644 | 
 | --- a/third_party/libopenjpeg/j2k.c | 
 | +++ b/third_party/libopenjpeg/j2k.c | 
 | @@ -9882,6 +9882,12 @@ static OPJ_BOOL opj_j2k_update_image_data(opj_tcd_t * p_tcd, | 
 |           * */ | 
 |          assert(res_x0 >= 0); | 
 |          assert(res_x1 >= 0); | 
 | + | 
 | +        /* Prevent bad casting to unsigned values in the subsequent lines. */ | 
 | +        if ( res_x0 < 0 || res_x1 < 0 || res_y0 < 0 || res_y1 < 0 ) { | 
 | +            return OPJ_FALSE; | 
 | +        } | 
 | + | 
 |          if (l_x0_dest < (OPJ_UINT32)res_x0) { | 
 |              l_start_x_dest = (OPJ_UINT32)res_x0 - l_x0_dest; | 
 |              l_offset_x0_src = 0; |