diff --git a/repos/libports/include/libc-plugin/fd_alloc.h b/repos/libports/include/libc-plugin/fd_alloc.h
index c906fd5442..b3c0a02cb9 100644
--- a/repos/libports/include/libc-plugin/fd_alloc.h
+++ b/repos/libports/include/libc-plugin/fd_alloc.h
@@ -49,6 +49,7 @@ namespace Libc {
 
 		void path(char const *newpath)
 		{
+			if (fd_path) { Genode::warning("may leak former FD path memory"); }
 			if (newpath) {
 				Genode::size_t const path_size = ::strlen(newpath) + 1;
 				char *buf = (char*)malloc(path_size);
diff --git a/repos/libports/src/lib/libc/vfs_plugin.h b/repos/libports/src/lib/libc/vfs_plugin.h
index 389ef5c657..10e583b75e 100644
--- a/repos/libports/src/lib/libc/vfs_plugin.h
+++ b/repos/libports/src/lib/libc/vfs_plugin.h
@@ -66,6 +66,7 @@ class Libc::Vfs_plugin : public Libc::Plugin
 				 * We have to allocate the path from the libc (done via 'strdup')
 				 * such that the path can be freed when an stdio fd is closed.
 				 */
+				if (fd->fd_path) { Genode::warning("may leak former FD path memory"); }
 				fd->fd_path = strdup(path.string());
 
 			} catch (Xml_node::Nonexistent_attribute) { }