diff --git a/third_party/libopenjpeg20/j2k.c b/third_party/libopenjpeg20/j2k.c
index ad6e1b86f..bf1cb4f36 100644
--- a/third_party/libopenjpeg20/j2k.c
+++ b/third_party/libopenjpeg20/j2k.c
@@ -9086,6 +9086,12 @@ 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;