diff --git a/src/shared/ask-password-api.c b/src/shared/ask-password-api.c
index ab0c34692f1..6c0a3699029 100644
--- a/src/shared/ask-password-api.c
+++ b/src/shared/ask-password-api.c
@@ -80,7 +80,7 @@ static int retrieve_key(key_serial_t serial, char ***ret) {
                 if (n < m)
                         break;
 
-                explicit_bzero_safe(p, n);
+                explicit_bzero_safe(p, m);
 
                 if (m > LONG_MAX / 2) /* overflow check */
                         return -ENOMEM;