fix(api): reject cloudflare api key in token field

- Add serializer validation for Cloudflare api_token values

- Reject 32-character hexadecimal values in token credentials

- Add serializer tests for valid token and api key-shaped token

api/src/backend/api/tests/test_serializers.py

@@ -2,7 +2,7 @@ import pytest
 from rest_framework.exceptions import ValidationError
 
 from api.v1.serializer_utils.integrations import S3ConfigSerializer
-from api.v1.serializers import ImageProviderSecret
+from api.v1.serializers import CloudflareTokenProviderSecret, ImageProviderSecret
 
 
 class TestS3ConfigSerializer:
@@ -133,3 +133,20 @@ class TestImageProviderSecret:
         serializer = ImageProviderSecret(data={"registry_password": "pass"})
         assert not serializer.is_valid()
         assert "non_field_errors" in serializer.errors
+
+
+class TestCloudflareProviderSecret:
+    """Test cases for Cloudflare provider credential formats."""
+
+    def test_valid_api_token(self):
+        serializer = CloudflareTokenProviderSecret(
+            data={"api_token": "Sn3lZJTBX6kkg7OdcBUAxOO963GEIyGQqnFTOFYY"}
+        )
+        assert serializer.is_valid(), serializer.errors
+
+    def test_invalid_api_token_with_api_key_format(self):
+        serializer = CloudflareTokenProviderSecret(
+            data={"api_token": "144c9defac04969c7bfad8efaa8ea194"}
+        )
+        assert not serializer.is_valid()
+        assert "api_token" in serializer.errors

api/src/backend/api/v1/serializers.py

@@ -1,5 +1,6 @@
 import base64
 import json
+import re
 from datetime import datetime, timedelta, timezone
 
 from django.conf import settings
@@ -1704,6 +1705,15 @@ class OracleCloudProviderSecret(serializers.Serializer):
 class CloudflareTokenProviderSecret(serializers.Serializer):
     api_token = serializers.CharField()
 
+    def validate_api_token(self, value: str) -> str:
+        # Cloudflare Global API Key is 32 hex chars; reject it in token field.
+        if re.fullmatch(r"[a-fA-F0-9]{32}", (value or "").strip()):
+            raise serializers.ValidationError(
+                "This value matches Cloudflare API Key format. "
+                "Use 'api_key' and 'api_email' instead."
+            )
+        return value
+
     class Meta:
         resource_name = "provider-secrets"