[SECURITY] Prevent access to arbitrary cached files by UUID (CVE-2025-14881)

src/pretix/api/views/exporters.py

@@ -74,6 +74,11 @@ class ExportersMixin:
     @action(detail=True, methods=['GET'], url_name='download', url_path='download/(?P<asyncid>[^/]+)/(?P<cfid>[^/]+)')
     def download(self, *args, **kwargs):
         cf = get_object_or_404(CachedFile, id=kwargs['cfid'])
+        if not cf.allowed_for_session(self.request, "exporters-api"):
+            return Response(
+                {'status': 'failed', 'message': 'Unknown file ID or export failed'},
+                status=status.HTTP_410_GONE
+            )
         if cf.file:
             resp = ChunkBasedFileResponse(cf.file.file, content_type=cf.type)
             resp['Content-Disposition'] = 'attachment; filename="{}"'.format(cf.filename).encode("ascii", "ignore")
@@ -109,7 +114,8 @@ class ExportersMixin:
         serializer = JobRunSerializer(exporter=instance, data=self.request.data, **self.get_serializer_kwargs())
         serializer.is_valid(raise_exception=True)
 
-        cf = CachedFile(web_download=False)
+        cf = CachedFile(web_download=True)
+        cf.bind_to_session(self.request, "exporters-api")
         cf.date = now()
         cf.expires = now() + timedelta(hours=24)
         cf.save()

src/pretix/base/models/base.py

@@ -59,6 +59,37 @@ class CachedFile(models.Model):
     web_download = models.BooleanField(default=True)  # allow web download, True for backwards compatibility in plugins
     session_key = models.TextField(null=True, blank=True)  # only allow download in this session
 
+    def session_key_for_request(self, request, salt=None):
+        from ...api.models import OAuthAccessToken, OAuthApplication
+        from .devices import Device
+        from .organizer import TeamAPIToken
+
+        if hasattr(request, "auth") and isinstance(request.auth, OAuthAccessToken):
+            k = f'app:{request.auth.application.pk}'
+        elif hasattr(request, "auth") and isinstance(request.auth, OAuthApplication):
+            k = f'app:{request.auth.pk}'
+        elif hasattr(request, "auth") and isinstance(request.auth, TeamAPIToken):
+            k = f'token:{request.auth.pk}'
+        elif hasattr(request, "auth") and isinstance(request.auth, Device):
+            k = f'device:{request.auth.pk}'
+        elif request.session.session_key:
+            k = request.session.session_key
+        else:
+            raise ValueError("No auth method found to bind to")
+
+        if salt:
+            k = f"{k}!{salt}"
+        return k
+
+    def allowed_for_session(self, request, salt=None):
+        return (
+            not self.session_key or
+            self.session_key_for_request(request, salt) == self.session_key
+        )
+
+    def bind_to_session(self, request, salt=None):
+        self.session_key = self.session_key_for_request(request, salt)
+
 
 @receiver(post_delete, sender=CachedFile)
 def cached_file_delete(sender, instance, **kwargs):

src/pretix/base/views/cachedfiles.py

@@ -36,9 +36,8 @@ class DownloadView(TemplateView):
     def object(self) -> CachedFile:
         try:
             o = get_object_or_404(CachedFile, id=self.kwargs['id'], web_download=True)
-            if o.session_key:
+            if not o.allowed_for_session(self.request):
-                if o.session_key != self.request.session.session_key:
+                raise Http404()
-                    raise Http404()
             return o
         except (ValueError, ValidationError):   # Invalid URLs
             raise Http404()

src/pretix/control/views/modelimport.py

@@ -38,6 +38,7 @@ from datetime import timedelta
 
 from django.conf import settings
 from django.contrib import messages
+from django.http import Http404
 from django.shortcuts import get_object_or_404, redirect
 from django.urls import reverse
 from django.utils.functional import cached_property
@@ -85,6 +86,7 @@ class BaseImportView(TemplateView):
             filename='import.csv',
             type='text/csv',
         )
+        cf.bind_to_session(request, "modelimport")
         cf.file.save('import.csv', request.FILES['file'])
 
         if self.request.POST.get("charset") in ENCODINGS:
@@ -137,7 +139,10 @@ class BaseProcessView(AsyncAction, FormView):
 
     @cached_property
     def file(self):
-        return get_object_or_404(CachedFile, pk=self.kwargs.get("file"), filename="import.csv")
+        cf = get_object_or_404(CachedFile, pk=self.kwargs.get("file"), filename="import.csv")
+        if not cf.allowed_for_session(self.request, "modelimport"):
+            raise Http404()
+        return cf
 
     @cached_property
     def parsed(self):

src/pretix/control/views/pdf.py

@@ -247,7 +247,7 @@ class BaseEditorView(EventPermissionRequiredMixin, TemplateView):
         cf = None
         if request.POST.get("background", "").strip():
             try:
-                cf = CachedFile.objects.get(id=request.POST.get("background"))
+                cf = CachedFile.objects.get(id=request.POST.get("background"), web_download=True)
             except CachedFile.DoesNotExist:
                 pass
 

src/pretix/control/views/shredder.py

@@ -38,7 +38,8 @@ from collections import OrderedDict
 from zipfile import ZipFile
 
 from django.contrib import messages
-from django.shortcuts import get_object_or_404, redirect
+from django.http import Http404
+from django.shortcuts import redirect
 from django.urls import reverse
 from django.utils.functional import cached_property
 from django.utils.translation import get_language, gettext_lazy as _
@@ -94,6 +95,8 @@ class ShredDownloadView(RecentAuthenticationRequiredMixin, EventPermissionRequir
             cf = CachedFile.objects.get(pk=kwargs['file'])
         except CachedFile.DoesNotExist:
             raise ShredError(_("The download file could no longer be found on the server, please try to start again."))
+        if not cf.allowed_for_session(self.request):
+            raise Http404()
 
         with ZipFile(cf.file.file, 'r') as zipfile:
             indexdata = json.loads(zipfile.read('index.json').decode())
@@ -111,7 +114,7 @@ class ShredDownloadView(RecentAuthenticationRequiredMixin, EventPermissionRequir
         ctx = super().get_context_data(**kwargs)
         ctx['shredders'] = self.shredders
         ctx['download_on_shred'] = any(shredder.require_download_confirmation for shredder in shredders)
-        ctx['file'] = get_object_or_404(CachedFile, pk=kwargs.get("file"))
+        ctx['file'] = cf
         return ctx