diff --git a/src/storage/storage_backend_iscsi.c b/src/storage/storage_backend_iscsi.c
index 6242cd0fac26b2b4fab6d4b0c9c64a8685b5cea1..55fe47f5e107200e59ac9980b60fe3a17f93e649 100644
--- a/src/storage/storage_backend_iscsi.c
+++ b/src/storage/storage_backend_iscsi.c
@@ -303,6 +303,11 @@ virStorageBackendISCSISetAuth(const char *portal,
                                  &secret_value, &secret_size) < 0)
         goto cleanup;
 
+    if (VIR_REALLOC_N(secret_value, secret_size + 1) < 0)
+        goto cleanup;
+
+    secret_value[secret_size] = '\0';
+
     if (virISCSINodeUpdate(portal,
                            source->devices[0].path,
                            "node.session.auth.authmethod",
diff --git a/src/storage/storage_backend_iscsi_direct.c b/src/storage/storage_backend_iscsi_direct.c
index 1624066e9c06b85b427436ed36f1522e6df5167f..0d7d6ba9c36e83727891c6aff9df5017af61221f 100644
--- a/src/storage/storage_backend_iscsi_direct.c
+++ b/src/storage/storage_backend_iscsi_direct.c
@@ -115,6 +115,11 @@ virStorageBackendISCSIDirectSetAuth(struct iscsi_context *iscsi,
                                  &secret_value, &secret_size) < 0)
         goto cleanup;
 
+    if (VIR_REALLOC_N(secret_value, secret_size + 1) < 0)
+        goto cleanup;
+
+    secret_value[secret_size] = '\0';
+
     if (iscsi_set_initiator_username_pwd(iscsi,
                                          authdef->username,
                                          (const char *)secret_value) < 0) {