diff --git a/kitsune/community/views.py b/kitsune/community/views.py
index 737470c289a..485cca542dc 100644
--- a/kitsune/community/views.py
+++ b/kitsune/community/views.py
@@ -15,7 +15,7 @@
 from kitsune.search.base import SumoSearchPaginator
 from kitsune.search.search import ProfileSearch
 from kitsune.sumo.parser import get_object_fallback
-from kitsune.sumo.utils import paginate
+from kitsune.sumo.utils import paginate, strip_nul_bytes
 from kitsune.users.models import ContributionAreas
 from kitsune.wiki.models import Document
 
@@ -31,7 +31,7 @@ def home(request):
 
     community_news = get_object_fallback(Document, COMMUNITY_NEWS_DOC, request.LANGUAGE_CODE)
     locale = _validate_locale(request.GET.get("locale"))
-    product = request.GET.get("product")
+    product = strip_nul_bytes(request.GET.get("product"))
     if product:
         product = get_object_or_404(Product, slug=product)
 
@@ -107,7 +107,7 @@ def top_contributors(request, area):
     page_size = 100
 
     locale = _validate_locale(request.GET.get("locale"))
-    product = request.GET.get("product")
+    product = strip_nul_bytes(request.GET.get("product"))
     if product:
         product = get_object_or_404(Product, slug=product)
 
diff --git a/kitsune/dashboards/views.py b/kitsune/dashboards/views.py
index 99336a6dc5f..cba2d5a556d 100644
--- a/kitsune/dashboards/views.py
+++ b/kitsune/dashboards/views.py
@@ -18,8 +18,9 @@
 )
 from kitsune.dashboards.utils import get_locales_by_visit, render_readouts
 from kitsune.products.models import Product
+from kitsune.sumo.i18n import normalize_language
 from kitsune.sumo.urlresolvers import reverse
-from kitsune.sumo.utils import smart_int
+from kitsune.sumo.utils import smart_int, strip_nul_bytes
 from kitsune.wiki.config import CATEGORIES
 
 log = logging.getLogger("k.dashboards")
@@ -178,11 +179,12 @@ def wiki_rows(request, readout_slug):
     """Return the table contents HTML for the given readout and mode."""
     product = _get_product(request)
 
+    locale = normalize_language(request.GET.get("locale"))
     readout = _kb_readout(
         request,
         readout_slug,
         READOUTS,
-        locale=request.GET.get("locale"),
+        locale=locale,
         mode=smart_int(request.GET.get("mode"), None),
         product=product,
     )
@@ -247,7 +249,7 @@ def aggregated_metrics(request):
 
 
 def _get_product(request):
-    product_slug = request.GET.get("product")
+    product_slug = strip_nul_bytes(request.GET.get("product"))
     if product_slug:
         return get_object_or_404(Product, slug=product_slug)
 
diff --git a/kitsune/flagit/models.py b/kitsune/flagit/models.py
index 4f5a7c965d9..a0ad66f46b4 100644
--- a/kitsune/flagit/models.py
+++ b/kitsune/flagit/models.py
@@ -29,6 +29,7 @@ class FlaggedObject(ModelBase):
         (REASON_ABUSE, _lazy("Abusive content")),
         (REASON_OTHER, _lazy("Other (please specify)")),
     )
+    VALID_REASONS = frozenset(key for key, _ in REASONS)
 
     FLAG_PENDING = 0
     FLAG_ACCEPTED = 1
diff --git a/kitsune/flagit/views.py b/kitsune/flagit/views.py
index ffe9f4505e9..d85521adffe 100644
--- a/kitsune/flagit/views.py
+++ b/kitsune/flagit/views.py
@@ -29,7 +29,7 @@
 from kitsune.questions.models import Answer, Question
 from kitsune.sumo.templatetags.jinja_helpers import urlparams
 from kitsune.sumo.urlresolvers import reverse
-from kitsune.sumo.utils import paginate
+from kitsune.sumo.utils import paginate, strip_nul_bytes
 from kitsune.tags.models import SumoTag
 
 
@@ -132,6 +132,8 @@ def flag(request, content_type=None, model=None, object_id=None, **kwargs):
 def flagged_queue(request):
     """Display the flagged queue with optimized queries."""
     reason = request.GET.get("reason")
+    if reason and reason not in FlaggedObject.VALID_REASONS:
+        reason = None
     content_type_id = request.GET.get("content_type")
 
     content_types = None
@@ -228,8 +230,8 @@ def build_hierarchy(parent_id=None, level=0):
 @require_http_methods(["GET", "POST"])
 def moderate_content(request):
     """Display flagged content that needs moderation."""
-    product_slug = request.GET.get("product")
-    assignee = request.GET.get("assignee")
+    product_slug = strip_nul_bytes(request.GET.get("product"))
+    assignee = strip_nul_bytes(request.GET.get("assignee"))
 
     if (
         assignee
diff --git a/kitsune/gallery/api.py b/kitsune/gallery/api.py
index 668707e8117..bf003356e93 100644
--- a/kitsune/gallery/api.py
+++ b/kitsune/gallery/api.py
@@ -44,7 +44,7 @@ def get_queryset(self):
         # locale may come from the Accept-language header, but it can be
         # overridden via the query string.
         locale = normalize_language(self.get_locale())
-        locale = self.request.query_params.get("locale", locale)
+        locale = normalize_language(self.request.query_params.get("locale")) or locale
         if locale is not None:
             queryset = queryset.filter(locale=locale)
 
diff --git a/kitsune/gallery/views.py b/kitsune/gallery/views.py
index eac69963168..56ede467ac1 100644
--- a/kitsune/gallery/views.py
+++ b/kitsune/gallery/views.py
@@ -20,8 +20,9 @@
 from kitsune.gallery.forms import ImageForm
 from kitsune.gallery.models import Image, Video
 from kitsune.gallery.utils import check_media_permissions, upload_image
+from kitsune.sumo.i18n import normalize_language
 from kitsune.sumo.urlresolvers import reverse
-from kitsune.sumo.utils import paginate
+from kitsune.sumo.utils import paginate, strip_nul_bytes
 from kitsune.upload.tasks import compress_image, generate_thumbnail
 from kitsune.upload.utils import FileTooLargeError
 from kitsune.wiki.tasks import schedule_rebuild_kb
@@ -114,8 +115,8 @@ def gallery_async(request):
     """
     # Maybe refactor this into existing views and check request.is_ajax?
     media_type = request.GET.get("type", "image")
-    term = request.GET.get("q")
-    media_locale = request.GET.get("locale", settings.WIKI_DEFAULT_LANGUAGE)
+    term = strip_nul_bytes(request.GET.get("q"))
+    media_locale = normalize_language(request.GET.get("locale")) or settings.WIKI_DEFAULT_LANGUAGE
     if media_type == "image":
         media_qs = Image.objects
     elif media_type == "video":
@@ -136,7 +137,7 @@ def gallery_async(request):
 def search(request, media_type):
     """Search the media gallery."""
 
-    term = request.GET.get("q")
+    term = strip_nul_bytes(request.GET.get("q", ""))
     if not term:
         url = reverse("gallery.gallery", args=[media_type])
         return HttpResponseRedirect(url)
diff --git a/kitsune/kpi/api.py b/kitsune/kpi/api.py
index 157c22f8c05..5738233fca6 100644
--- a/kitsune/kpi/api.py
+++ b/kitsune/kpi/api.py
@@ -31,6 +31,8 @@
 )
 from kitsune.questions.models import Answer, AnswerVote, Question
 from kitsune.sumo.api_utils import OrderingFilter
+from kitsune.sumo.i18n import normalize_language
+from kitsune.sumo.utils import strip_nul_bytes
 from kitsune.wiki.models import HelpfulVote
 
 
@@ -124,8 +126,8 @@ class QuestionsMetricList(CachedAPIView):
 
     def get_objects(self, request):
         # Set up the queries for the data we need
-        locale = request.GET.get("locale")
-        product = request.GET.get("product")
+        locale = normalize_language(request.GET.get("locale"))
+        product = strip_nul_bytes(request.GET.get("product"))
 
         # Set up the query for the data we need.
         qs = _daily_qs_for(Question)
@@ -191,8 +193,8 @@ class KBVoteMetricList(CachedAPIView):
 
     def get_objects(self, request):
         # Set up the queries for the data we need
-        locale = request.GET.get("locale")
-        product = request.GET.get("product")
+        locale = normalize_language(request.GET.get("locale"))
+        product = strip_nul_bytes(request.GET.get("product"))
 
         # Use "__range" to ensure the database index is used in Postgres,
         # and only show the helpful votes from the last 365 days.
diff --git a/kitsune/messages/api.py b/kitsune/messages/api.py
index 98e59a0c3aa..61a1d69df6c 100644
--- a/kitsune/messages/api.py
+++ b/kitsune/messages/api.py
@@ -5,7 +5,7 @@
 
 from kitsune.access.decorators import login_required
 from kitsune.sumo.decorators import json_view
-from kitsune.sumo.utils import webpack_static
+from kitsune.sumo.utils import strip_nul_bytes, webpack_static
 from kitsune.users.templatetags.jinja_helpers import profile_avatar
 
 
@@ -14,7 +14,7 @@
 @json_view
 def get_autocomplete_suggestions(request):
     """An API to provide auto-complete data for user names or groups."""
-    pre = request.GET.get("term", "") or request.GET.get("query", "")
+    pre = strip_nul_bytes(request.GET.get("term", "") or request.GET.get("query", ""))
     if not pre or not request.user.is_authenticated:
         return []
 
diff --git a/kitsune/postcrash/views.py b/kitsune/postcrash/views.py
index 371406ae041..f1eefb8d56f 100644
--- a/kitsune/postcrash/views.py
+++ b/kitsune/postcrash/views.py
@@ -3,11 +3,12 @@
 from django.views.decorators.cache import cache_page
 
 from kitsune.postcrash.models import Signature
+from kitsune.sumo.utils import strip_nul_bytes
 
 
 @cache_page(60 * 60 * 24)  # One day.
 def api(request):
-    s = request.GET.get("s", None)
+    s = strip_nul_bytes(request.GET.get("s", None))
     if not s:
         return HttpResponseBadRequest(content_type="text/plain")
 
diff --git a/kitsune/questions/feeds.py b/kitsune/questions/feeds.py
index ecf937459fa..ca3208c8b71 100644
--- a/kitsune/questions/feeds.py
+++ b/kitsune/questions/feeds.py
@@ -11,6 +11,7 @@
 from kitsune.sumo.feeds import Feed
 from kitsune.sumo.templatetags.jinja_helpers import urlparams
 from kitsune.sumo.urlresolvers import reverse
+from kitsune.sumo.utils import strip_nul_bytes
 from kitsune.tags.models import SumoTag
 
 
@@ -27,8 +28,8 @@ class QuestionsFeed(Feed):
     def get_object(self, request):
         query = {}
 
-        product_slug = request.GET.get("product")
-        topic_slug = request.GET.get("topic")
+        product_slug = strip_nul_bytes(request.GET.get("product"))
+        topic_slug = strip_nul_bytes(request.GET.get("topic"))
         locale = request.LANGUAGE_CODE
 
         if product_slug and product_slug != "all":
diff --git a/kitsune/questions/views.py b/kitsune/questions/views.py
index fbb749ed429..ba97fd7d14d 100644
--- a/kitsune/questions/views.py
+++ b/kitsune/questions/views.py
@@ -59,6 +59,7 @@
     get_mobile_product_from_ua,
 )
 from kitsune.sumo.decorators import ratelimit
+from kitsune.sumo.i18n import normalize_language
 from kitsune.sumo.templatetags.jinja_helpers import urlparams
 from kitsune.sumo.urlresolvers import reverse
 from kitsune.sumo.utils import (
@@ -69,6 +70,7 @@
     paginate,
     set_aaq_context,
     simple_paginate,
+    strip_nul_bytes,
 )
 from kitsune.tags.models import SumoTag
 from kitsune.tags.utils import add_existing_tag
@@ -173,9 +175,9 @@ def question_list(request, product_slug=None, topic_slug=None):
     if show not in FILTER_GROUPS:
         show = "needs-attention"
 
-    tagged = request.GET.get("tagged")
+    tagged = strip_nul_bytes(request.GET.get("tagged"))
     tags = None
-    topic_slug = request.GET.get("topic", "") or topic_slug
+    topic_slug = strip_nul_bytes(request.GET.get("topic")) or topic_slug
 
     order = request.GET.get("order", "updated")
     if order not in ORDER_BY:
@@ -587,7 +589,7 @@ def aaq(request, product_slug=None, step=1, is_loginless=False):
 
     # Check if the user is using a mobile device,
     # render step 2 if they are
-    product_slug = product_slug or request.GET.get("product")
+    product_slug = product_slug or strip_nul_bytes(request.GET.get("product"))
     if product_slug is None:
         change_product = False
         if request.GET.get("q") == "change_product":
@@ -702,7 +704,7 @@ def aaq(request, product_slug=None, step=1, is_loginless=False):
             )
 
         if (
-            (from_locale := request.GET.get("from_locale"))
+            (from_locale := normalize_language(request.GET.get("from_locale")))
             and from_locale != request.LANGUAGE_CODE
             and product.questions_enabled(locale=from_locale)
         ):
@@ -1008,7 +1010,7 @@ def solve(request, question_id, answer_id):
     """Accept an answer as the solution to the question."""
 
     if not (
-        ((request.method == "GET") and (watch_secret := request.GET.get("watch", None)))
+        ((request.method == "GET") and (watch_secret := strip_nul_bytes(request.GET.get("watch", None))))
         or (
             (request.method == "POST")
             and (request.user.is_authenticated and request.user.is_active)
@@ -1100,11 +1102,11 @@ def question_vote(request, question_id):
         vote.save()
 
         if "referrer" in request.GET:
-            referrer = request.GET.get("referrer")
+            referrer = strip_nul_bytes(request.GET.get("referrer"))
             vote.add_metadata("referrer", referrer)
 
             if referrer == "search" and "query" in request.GET:
-                vote.add_metadata("query", request.GET.get("query"))
+                vote.add_metadata("query", strip_nul_bytes(request.GET.get("query")))
 
         ua = request.META.get("HTTP_USER_AGENT")
         if ua:
@@ -1166,11 +1168,11 @@ def answer_vote(request, question_id, answer_id):
         vote.save()
 
         if "referrer" in request.GET:
-            referrer = request.GET.get("referrer")
+            referrer = strip_nul_bytes(request.GET.get("referrer"))
             vote.add_metadata("referrer", referrer)
 
             if referrer == "search" and "query" in request.GET:
-                vote.add_metadata("query", request.GET.get("query"))
+                vote.add_metadata("query", strip_nul_bytes(request.GET.get("query")))
 
         ua = request.META.get("HTTP_USER_AGENT")
         if ua:
@@ -1594,7 +1596,7 @@ def metrics(request, locale_code=None):
     """The Support Forum metrics dashboard."""
     template = "questions/metrics.html"
 
-    product = request.GET.get("product")
+    product = strip_nul_bytes(request.GET.get("product"))
     if product:
         product = get_object_or_404(Product, slug=product)
 
diff --git a/kitsune/sumo/utils.py b/kitsune/sumo/utils.py
index d985f8a8340..34d04b00029 100644
--- a/kitsune/sumo/utils.py
+++ b/kitsune/sumo/utils.py
@@ -160,6 +160,13 @@ class TruncationException(Exception):
     pass
 
 
+def strip_nul_bytes(value):
+    """Strip NUL bytes from a string to prevent database errors."""
+    if value is None:
+        return None
+    return value.replace("\x00", "")
+
+
 def truncated_json_dumps(obj, max_length, key, ensure_ascii=False):
     """Dump an object to JSON, and ensure the dump is less than ``max_length``.
 
diff --git a/kitsune/users/api.py b/kitsune/users/api.py
index c15d311bb12..728bff80deb 100644
--- a/kitsune/users/api.py
+++ b/kitsune/users/api.py
@@ -27,6 +27,7 @@
 from kitsune.questions.utils import num_answers, num_questions, num_solutions
 from kitsune.sumo.api_utils import DateTimeUTCField, OrderingFilter, PermissionMod
 from kitsune.sumo.decorators import json_view
+from kitsune.sumo.utils import strip_nul_bytes
 from kitsune.users.models import Profile, Setting
 from kitsune.users.templatetags.jinja_helpers import profile_avatar
 
@@ -54,8 +55,8 @@ def to_internal_value(self, data):
 @json_view
 def usernames(request):
     """An API to provide auto-complete data for user names."""
-    term = request.GET.get("term", "")
-    query = request.GET.get("query", "")
+    term = strip_nul_bytes(request.GET.get("term", ""))
+    query = strip_nul_bytes(request.GET.get("query", ""))
     pre = term or query
 
     if not pre:
diff --git a/kitsune/wiki/api.py b/kitsune/wiki/api.py
index b49daa790a1..5185d4343e1 100644
--- a/kitsune/wiki/api.py
+++ b/kitsune/wiki/api.py
@@ -6,6 +6,7 @@
 from kitsune.products.models import Product, Topic
 from kitsune.sumo.api_utils import GenericAPIException, LocaleNegotiationMixin
 from kitsune.sumo.i18n import normalize_language
+from kitsune.sumo.utils import strip_nul_bytes
 from kitsune.wiki.config import REDIRECT_HTML
 from kitsune.wiki.models import Document
 
@@ -37,26 +38,26 @@ class DocumentList(LocaleNegotiationMixin, generics.ListAPIView):
     serializer_class = DocumentShortSerializer
 
     def get_queryset(self):
-        locales = self.request.query_params.get("locales")
+        locales = strip_nul_bytes(self.request.query_params.get("locales"))
         if locales:
             # Multiple locales are separated by commas.
             locales = locales.replace(",", " ").split()
         elif locale := normalize_language(self.get_locale()):
             locales = [locale]
 
-        categories = self.request.query_params.get("categories")
+        categories = strip_nul_bytes(self.request.query_params.get("categories"))
         if categories:
             # Multiple categories are separated by commas.
             categories = categories.replace(",", " ").split()
         else:
             categories = settings.IA_DEFAULT_CATEGORIES
 
-        product = self.request.query_params.get("product")
-        topic = self.request.query_params.get("topic")
+        product = strip_nul_bytes(self.request.query_params.get("product"))
+        topic = strip_nul_bytes(self.request.query_params.get("topic"))
         is_template = bool(self.request.query_params.get("is_template", False))
         is_archived = bool(self.request.query_params.get("is_archived", False))
         is_redirect = bool(self.request.query_params.get("is_redirect", False))
-        title_query = self.request.query_params.get("q")
+        title_query = strip_nul_bytes(self.request.query_params.get("q"))
 
         queryset = Document.objects.visible(self.request.user, category__in=categories)
 
diff --git a/kitsune/wiki/views.py b/kitsune/wiki/views.py
index a45256fdd8c..3f822224272 100644
--- a/kitsune/wiki/views.py
+++ b/kitsune/wiki/views.py
@@ -38,6 +38,7 @@
     paginate,
     set_aaq_context,
     smart_int,
+    strip_nul_bytes,
     truncated_json_dumps,
 )
 from kitsune.users.models import Profile
@@ -226,8 +227,8 @@ def maybe_vary_on_accept_language(response):
         return maybe_vary_on_accept_language(HttpResponseRedirect(url))
 
     # Get "redirected from" doc if we were redirected:
-    redirect_slug = request.GET.get("redirectslug")
-    redirect_locale = request.GET.get("redirectlocale")
+    redirect_slug = strip_nul_bytes(request.GET.get("redirectslug"))
+    redirect_locale = normalize_language(request.GET.get("redirectlocale"))
     redirected_from = None
     if redirect_slug and redirect_locale:
         try:
@@ -696,7 +697,7 @@ def preview_revision(request):
 @require_GET
 def document_revisions(request, document_slug, contributor_form=None):
     """List all the revisions of a given document."""
-    locale = request.GET.get("locale", request.LANGUAGE_CODE)
+    locale = normalize_language(request.GET.get("locale")) or request.LANGUAGE_CODE
 
     doc = get_visible_document_or_404(
         request.user,
@@ -888,7 +889,7 @@ def compare_revisions(request, document_slug):
     The ids are passed as query string parameters (to and from).
 
     """
-    locale = request.GET.get("locale", request.LANGUAGE_CODE)
+    locale = normalize_language(request.GET.get("locale")) or request.LANGUAGE_CODE
     doc = get_visible_document_or_404(request.user, locale=locale, slug=document_slug)
     if "from" not in request.GET or "to" not in request.GET:
         raise Http404
@@ -1266,9 +1267,9 @@ def json_view(request):
     """Return some basic document info in a JSON blob."""
     kwargs = {"locale": request.LANGUAGE_CODE, "current_revision__isnull": False}
     if "title" in request.GET:
-        kwargs["title"] = request.GET["title"]
+        kwargs["title"] = strip_nul_bytes(request.GET["title"])
     elif "slug" in request.GET:
-        kwargs["slug"] = request.GET["slug"]
+        kwargs["slug"] = strip_nul_bytes(request.GET["slug"])
     else:
         return HttpResponseBadRequest()
 
@@ -1773,7 +1774,7 @@ def recent_revisions(request):
 @require_GET
 def what_links_here(request, document_slug):
     """List all documents that link to a document."""
-    locale = request.GET.get("locale", request.LANGUAGE_CODE)
+    locale = normalize_language(request.GET.get("locale")) or request.LANGUAGE_CODE
 
     doc = get_visible_document_or_404(
         request.user,