diff --git a/ykcs11/token_vendors.c b/ykcs11/token_vendors.c
index b5bbfd8..debcf50 100644
--- a/ykcs11/token_vendors.c
+++ b/ykcs11/token_vendors.c
@@ -12,12 +12,23 @@ static CK_RV COMMON_token_login(ykpiv_state *state, CK_USER_TYPE user, CK_UTF8CH
   int tries = 0; // TODO: this is effectively disregarded, should we add a better value in ykpiv_verify?
   unsigned char key[24];
   size_t key_len = sizeof(key);
+  unsigned char *term_pin;
 
   if (user == CKU_USER) {
-    if (ykpiv_verify(state, (char *)pin, &tries) != YKPIV_OK) {
+    // add null termination for the pin
+    term_pin = malloc(pin_len + 1);
+    if (term_pin == NULL) {
+      return CKR_HOST_MEMORY;
+    }
+    memcpy(term_pin, pin, pin_len);
+    term_pin[pin_len] = 0;
+
+    if (ykpiv_verify(state, (char *)term_pin, &tries) != YKPIV_OK) {
+      free(term_pin);
       DBG("Failed to login");
       return CKR_PIN_INCORRECT;
     }
+    free(term_pin);
   }
   else if (user == CKU_SO) {
     if(ykpiv_hex_decode((char *)pin, pin_len, key, &key_len) != YKPIV_OK) {