diff --git a/tests/lib/cbprintf_package/prj.conf b/tests/lib/cbprintf_package/prj.conf
index 9467c292689..ebaeb3fc3fc 100644
--- a/tests/lib/cbprintf_package/prj.conf
+++ b/tests/lib/cbprintf_package/prj.conf
@@ -1 +1,2 @@
 CONFIG_ZTEST=y
+CONFIG_CBPRINTF_LIBC_SUBSTS=y