diff --git a/maint/vm/ubuntu10.04/tox.ini b/maint/vm/ubuntu10.04/tox.ini
index 87841ac8..2ae1b27a 100644
--- a/maint/vm/ubuntu10.04/tox.ini
+++ b/maint/vm/ubuntu10.04/tox.ini
@@ -17,6 +17,7 @@ deps =
      pycurl
      simplejson
      twisted==11.0.0
+     zope.interface<4.0
 
 [testenv:py26-full]
 deps =
diff --git a/maint/vm/ubuntu12.04/tox.ini b/maint/vm/ubuntu12.04/tox.ini
index 9c8a312a..e30ef22a 100644
--- a/maint/vm/ubuntu12.04/tox.ini
+++ b/maint/vm/ubuntu12.04/tox.ini
@@ -17,6 +17,7 @@ deps =
      pycurl
      simplejson
      twisted==11.0.0
+     zope.interface<4.0
 
 [testenv:py27-full]
 basepython = python2.7