diff --git a/pandora/user/migrations/0004_jsonfield.py b/pandora/user/migrations/0004_jsonfield.py
index 90a5548a..99493930 100644
--- a/pandora/user/migrations/0004_jsonfield.py
+++ b/pandora/user/migrations/0004_jsonfield.py
@@ -6,6 +6,20 @@ import django.contrib.postgres.fields.jsonb
 from django.db import migrations, models
 
 
+def cleanup_sessiondata(apps, schema_editor):
+    SessionData = apps.get_model("user", "SessionData")
+    for data in SessionData.objects.all():
+        changed = False
+        plugins = []
+        for p in data.info.get('navigator', {}).get('plugins', []):
+            if p and '\x00' not in p:
+                plugins.append(p)
+            else:
+                changed = True
+        if changed:
+            data.info['navigator']['plugins'] = plugins
+            data.save()
+
 class Migration(migrations.Migration):
 
     dependencies = [
@@ -13,6 +27,7 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
+        migrations.RunPython(cleanup_sessiondata),
         migrations.RunSQL(
             'ALTER TABLE "user_sessiondata" ALTER COLUMN "info" TYPE jsonb USING "info"::text::jsonb'
         ),
diff --git a/pandora/user/models.py b/pandora/user/models.py
index 7994651c..44cd0fde 100644
--- a/pandora/user/models.py
+++ b/pandora/user/models.py
@@ -111,6 +111,11 @@ class SessionData(models.Model):
         info = json.loads(request.POST.get('data', '{}'))
         if info and isinstance(info, dict):
             data.info = info
+            if data.info.get('navigator', {}).get('plugins'):
+                data.info['navigator']['plugins'] = [
+                    p for p in data.info['navigator']['plugins']
+                    if p and '\x00' not in p
+                ]
         screen = data.info.get('screen', {})
         if screen and 'height' in screen and 'width' in screen:
             data.screensize = u'%s\xd7%s' % (screen['width'], screen['height'])