Security: Minor additional hardening (#13898)

* Security: bump jinja2 floor to 3.1.6 (CVE-2025-27516)

* Security: anchor the /share/ URL pattern

* Security: handle missing file on public share view without 500

* Security: scope correspondent last_correspondence to permitted documents

* Security: disable PUT/PATCH on share link bundles

src/documents/tests/test_api_objects.py

@@ -102,6 +102,7 @@ class TestApiObjects(DirectoriesMixin, APITestCase):
             - API is called
         THEN:
             - Last correspondence date is returned only if requested for list, and for detail
+            - The date is scoped to documents the requesting user may view
         """
 
         Document.objects.create(
@@ -145,6 +146,32 @@ class TestApiObjects(DirectoriesMixin, APITestCase):
             response.data["last_correspondence"],
         )
 
+        # A newer document owned by another user must not leak through the
+        # aggregate for a non-superuser who cannot view it
+        other = User.objects.create_user(username="other")
+        Document.objects.create(
+            mime_type="application/pdf",
+            correspondent=self.c1,
+            created=datetime.date(2023, 6, 1),
+            checksum="hidden",
+            owner=other,
+        )
+
+        user = User.objects.create_user(username="regular")
+        user.user_permissions.add(
+            Permission.objects.get(codename="view_correspondent"),
+        )
+        self.client.force_authenticate(user=user)
+
+        response = self.client.get("/api/correspondents/?last_correspondence=true")
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        result = next(r for r in response.data["results"] if r["id"] == self.c1.id)
+        self.assertIn("2022-01-02", result["last_correspondence"])
+
+        response = self.client.get(f"/api/correspondents/{self.c1.id}/")
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertIn("2022-01-02", response.data["last_correspondence"])
+
     def test_paginated_objects_include_all_only_for_legacy_version(self) -> None:
         response_v10 = self.client.get("/api/correspondents/")
         self.assertEqual(response_v10.status_code, status.HTTP_200_OK)

src/documents/tests/test_share_link_bundles.py

@@ -192,6 +192,50 @@ class ShareLinkBundleAPITests(DirectoriesMixin, APITestCase):
         self.assertEqual(response.status_code, status.HTTP_302_FOUND)
         self.assertIn("sharelink_notfound=1", response["Location"])
 
+    def test_share_link_missing_file_redirects(self) -> None:
+        """
+        GIVEN:
+            - A share link whose document file is missing from disk
+        WHEN:
+            - The public share link is requested anonymously
+        THEN:
+            - The user is redirected to login instead of a 500 error
+        """
+        doc = DocumentFactory.create(filename="missing-original.pdf")
+        share_link = ShareLink.objects.create(
+            slug="missingfilelink",
+            document=doc,
+            file_version=ShareLink.FileVersion.ORIGINAL,
+        )
+
+        self.client.logout()
+        response = self.client.get(f"/share/{share_link.slug}/")
+
+        self.assertEqual(response.status_code, status.HTTP_302_FOUND)
+        self.assertIn("sharelink_notfound=1", response["Location"])
+
+    def test_download_ready_bundle_missing_file_returns_503(self) -> None:
+        """
+        GIVEN:
+            - A READY bundle whose zip file is missing from disk
+        WHEN:
+            - The public share link is requested anonymously
+        THEN:
+            - A 503 is returned instead of a 500 error
+        """
+        bundle = ShareLinkBundle.objects.create(
+            slug="missingbundlefile",
+            file_version=ShareLink.FileVersion.ARCHIVE,
+            status=ShareLinkBundle.Status.READY,
+            file_path="bundles/gone.zip",
+        )
+        bundle.documents.set([self.document])
+
+        self.client.logout()
+        response = self.client.get(f"/share/{bundle.slug}/")
+
+        self.assertEqual(response.status_code, status.HTTP_503_SERVICE_UNAVAILABLE)
+
 
 class ShareLinkBundleTaskTests(DirectoriesMixin, APITestCase):
     def setUp(self) -> None: