diff --git a/sys/vfs/devfs/devfs_rules.c b/sys/vfs/devfs/devfs_rules.c
--- a/sys/vfs/devfs/devfs_rules.c
+++ b/sys/vfs/devfs/devfs_rules.c
@@ -191,7 +191,7 @@
 	if (templ->mntpoint == NULL)
 		return EINVAL;
 
-	mntpointlen = strlen(templ->mntpoint);
+	mntpointlen = strnlen(templ->mntpoint, PATH_MAX);
 	if (mntpointlen == 0)
 		return EINVAL;