diff --git a/scripts/extract-cert.c b/scripts/extract-cert.c
index b071bf4..3bc48c7 100644
--- a/scripts/extract-cert.c
+++ b/scripts/extract-cert.c
@@ -71,7 +71,7 @@
 static const char *key_pass;
 static BIO *wb;
 static char *cert_dst;
-int kbuild_verbose;
+static int kbuild_verbose;
 
 static void write_cert(X509 *x509)
 {