diff --git a/toolchain/gcc/patches/6.3.0/960-fix-ubsan-defref.patch b/toolchain/gcc/patches/6.3.0/960-fix-ubsan-defref.patch
new file mode 100644
index 0000000000..72d86c1498
--- /dev/null
+++ b/toolchain/gcc/patches/6.3.0/960-fix-ubsan-defref.patch
@@ -0,0 +1,11 @@
+--- a/gcc/ubsan.c
++++ b/gcc/ubsan.c
+@@ -1471,7 +1471,7 @@ ubsan_use_new_style_p (location_t loc)
+ 
+   expanded_location xloc = expand_location (loc);
+   if (xloc.file == NULL || strncmp (xloc.file, "\1", 2) == 0
+-      || xloc.file == '\0' || xloc.file[0] == '\xff'
++      || xloc.file[0] == '\0' || xloc.file[0] == '\xff'
+       || xloc.file[1] == '\xff')
+     return false;
+