diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c
index 4fbceb4bd9..a226e4d94a 100644
--- a/src/lxc/lxc_container.c
+++ b/src/lxc/lxc_container.c
@@ -940,6 +940,7 @@ static int lxcContainerMountFSBlockHelper(virDomainFSDefPtr fs,
     }
 
 cleanup:
+    VIR_FREE(format);
     return ret;
 }