diff --git a/third_party/libopenjpeg20/j2k.c b/third_party/libopenjpeg20/j2k.c
index 44de79a75..8e35b33ee 100644
--- a/third_party/libopenjpeg20/j2k.c
+++ b/third_party/libopenjpeg20/j2k.c
@@ -8914,6 +8914,12 @@ static OPJ_BOOL opj_j2k_update_image_data(opj_tcd_t * p_tcd, OPJ_BYTE * p_data,
          * */
         assert(l_res->x0 >= 0);
         assert(l_res->x1 >= 0);
+
+        /* Prevent bad casting to unsigned values in the subsequent lines. */
+        if ( l_res->x0 < 0 || l_res->x1 < 0 || l_res->y0 < 0 || l_res->y1 < 0 ) {
+            return OPJ_FALSE;
+        }
+
         if (l_x0_dest < (OPJ_UINT32)l_res->x0) {
             l_start_x_dest = (OPJ_UINT32)l_res->x0 - l_x0_dest;
             l_offset_x0_src = 0;