diff --git a/modoboa/maillog/graphics.py b/modoboa/maillog/graphics.py
index 9adf09af9..a4b537778 100644
--- a/modoboa/maillog/graphics.py
+++ b/modoboa/maillog/graphics.py
@@ -112,7 +112,7 @@ class Graphic:
             "--end",
             str(end),
         ] + cmdargs
-        code, output = exec_cmd(cmd, shell=True)
+        code, output = exec_cmd(cmd)
         if code:
             return []