diff --git a/xrdp/xrdp_newconfig.c b/xrdp/xrdp_newconfig.c
index b95368889..7da3a32c5 100644
--- a/xrdp/xrdp_newconfig.c
+++ b/xrdp/xrdp_newconfig.c
@@ -88,7 +88,8 @@ nc_load_gfx_x264_ct(toml_table_t *tfile, const int connection_type,
               "adopting the default value \"" X264_DEFAULT_PRESET "\"",
               rdpbcgr_connection_type_names[connection_type]);
         g_strncpy(param[connection_type].preset,
-                  X264_DEFAULT_PRESET, sizeof(X264_DEFAULT_PRESET) - 1);
+                  X264_DEFAULT_PRESET,
+                  sizeof(param[connection_type].preset) - 1);
     }
 
     /* tune */
@@ -107,7 +108,8 @@ nc_load_gfx_x264_ct(toml_table_t *tfile, const int connection_type,
               "adopting the default value \"" X264_DEFAULT_TUNE "\"",
               rdpbcgr_connection_type_names[connection_type]);
         g_strncpy(param[connection_type].tune,
-                  X264_DEFAULT_TUNE, sizeof(X264_DEFAULT_TUNE));
+                  X264_DEFAULT_TUNE,
+                  sizeof(param[connection_type].tune) - 1);
     }
 
     /* profile */
@@ -126,7 +128,8 @@ nc_load_gfx_x264_ct(toml_table_t *tfile, const int connection_type,
               "adopting the default value \"" X264_DEFAULT_PROFILE "\"",
               rdpbcgr_connection_type_names[connection_type]);
         g_strncpy(param[connection_type].profile,
-                  X264_DEFAULT_PROFILE, sizeof(X264_DEFAULT_PROFILE));
+                  X264_DEFAULT_PROFILE,
+                  sizeof(param[connection_type].profile) - 1);
     }
 
     /* vbv_max_bitrate */