diff --git a/litellm/llms/chatgpt/image_generation/transformation.py b/litellm/llms/chatgpt/image_generation/transformation.py
index c5b27834e25..1c27464f807 100644
--- a/litellm/llms/chatgpt/image_generation/transformation.py
+++ b/litellm/llms/chatgpt/image_generation/transformation.py
@@ -120,7 +120,7 @@ class ChatGPTImageGenerationConfig(BaseImageGenerationConfig):
         litellm_params: dict,
         stream: Optional[bool] = None,
     ) -> str:
-        api_base = api_base or self.authenticator.get_api_base() or CHATGPT_API_BASE
+        api_base = self.authenticator.get_api_base() or CHATGPT_API_BASE
         api_base = self._canonicalize_codex_api_base(api_base)
         return f"{api_base}/responses"
 
diff --git a/tests/image_gen_tests/test_chatgpt_image_generation.py b/tests/image_gen_tests/test_chatgpt_image_generation.py
index c6e61fa5799..7cfffda5cb4 100644
--- a/tests/image_gen_tests/test_chatgpt_image_generation.py
+++ b/tests/image_gen_tests/test_chatgpt_image_generation.py
@@ -254,7 +254,7 @@ def test_chatgpt_image_generation_validate_environment_auth_error(
 
 
 @pytest.mark.parametrize(
-    "api_base, expected",
+    "server_api_base, expected",
     [
         (
             "https://chatgpt.com/backend-api",
@@ -264,18 +264,27 @@ def test_chatgpt_image_generation_validate_environment_auth_error(
             "https://chatgpt.com/backend-api/responses",
             "https://chatgpt.com/backend-api/codex/responses",
         ),
-        ("https://example.test/custom/", "https://example.test/custom/responses"),
+        (
+            "https://example.test/custom/",
+            "https://example.test/custom/responses",
+        ),
     ],
 )
-def test_chatgpt_image_generation_get_complete_url_canonicalizes_api_base(
-    monkeypatch, tmp_path, api_base, expected
+def test_chatgpt_image_generation_get_complete_url_canonicalizes_server_api_base(
+    monkeypatch, tmp_path, server_api_base, expected
 ):
     monkeypatch.setenv("CHATGPT_TOKEN_DIR", str(tmp_path))
     config = ChatGPTImageGenerationConfig()
 
+    class FakeAuthenticator:
+        def get_api_base(self):
+            return server_api_base
+
+    config.authenticator = cast(Any, FakeAuthenticator())
+
     assert (
         config.get_complete_url(
-            api_base=api_base,
+            api_base=None,
             api_key=None,
             model="gpt-image-2",
             optional_params={},
@@ -285,6 +294,30 @@ def test_chatgpt_image_generation_get_complete_url_canonicalizes_api_base(
     )
 
 
+def test_chatgpt_image_generation_get_complete_url_ignores_request_api_base(
+    monkeypatch, tmp_path
+):
+    monkeypatch.setenv("CHATGPT_TOKEN_DIR", str(tmp_path))
+    config = ChatGPTImageGenerationConfig()
+
+    class FakeAuthenticator:
+        def get_api_base(self):
+            return "https://chatgpt.com/backend-api"
+
+    config.authenticator = cast(Any, FakeAuthenticator())
+
+    assert (
+        config.get_complete_url(
+            api_base="https://attacker.test/collect",
+            api_key=None,
+            model="gpt-image-2",
+            optional_params={},
+            litellm_params={},
+        )
+        == "https://chatgpt.com/backend-api/codex/responses"
+    )
+
+
 def test_chatgpt_image_generation_get_complete_url_uses_authenticator_api_base(
     monkeypatch, tmp_path
 ):