diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 667691baf15fa1f70f05425fdf6528c49049c5d6..c97d0f68b7bc15912d69c3faa73f0c8ba48de896 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6604,6 +6604,7 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
 
  cleanup:
     VIR_FREE(cpu);
+    virBufferFreeAndReset(&buf);
     return ret;
 }