diff --git a/misp_modules/modules/expansion/vulnerability_lookup.py b/misp_modules/modules/expansion/vulnerability_lookup.py
index b4821bc4f..6cc38e73f 100644
--- a/misp_modules/modules/expansion/vulnerability_lookup.py
+++ b/misp_modules/modules/expansion/vulnerability_lookup.py
@@ -39,6 +39,8 @@
         "it bounds alias lookup attempts, CPE results and each enrichment section. "
         "with_linked, with_comments, with_bundles, with_sightings, with_meta, with_epss and with_kev default to true; "
         "with_timeline defaults to false. Boolean options accept true/false or their string equivalents.\n"
+        "Unset options (null or blank strings from MISP) use their documented defaults. "
+        "The request's top-level timeout limits total module execution independently of config.timeout.\n"
         "CPE lookup uses cpe_source (default cvelistv5) and cpe_page (default 1). Results match vendor and product; "
         "exact version applicability must be checked. CPE search imports advisories from one bounded page; "
         "the optional community and priority lookups apply to vulnerability ID input.\n"
@@ -80,6 +82,13 @@ def handler(q=False):
     config = request.get("config") or {}
     if not isinstance(config, dict):
         return {"error": "Invalid module configuration."}
+    # MISP sends all advertised settings, including null/blank values for unset options.
+    # Keep explicit false and zero; they are meaningful configuration values.
+    config = {
+        key: value
+        for key, value in config.items()
+        if value is not None and not (isinstance(value, str) and not value.strip())
+    }
     try:
         timeout = float(config.get("timeout", 30))
         max_related = int(config.get("max_related", 50))
diff --git a/tests/test_vulnerability_lookup.py b/tests/test_vulnerability_lookup.py
index 5590b6edc..a27e90361 100644
--- a/tests/test_vulnerability_lookup.py
+++ b/tests/test_vulnerability_lookup.py
@@ -532,6 +532,68 @@ def test_custom_url_timeout_and_identifier_encoding_are_used_for_all_requests():
     assert objects(result, "vulnerability")
 
 
+def test_misp_null_configuration_reaches_the_api_and_keeps_default_enrichment():
+    query = {
+        "module": "vulnerability_lookup",
+        "attribute": {"type": "vulnerability", "value": CVE, "uuid": UUID},
+        "config": dict.fromkeys(vulnerability_lookup.moduleconfig),
+        "timeout": 10,
+    }
+    query["config"]["timeout"] = "80"
+    with patch("requests.get", side_effect=[response(cve()), response({}, 404), response({}, 404)]) as get:
+        result = vulnerability_lookup.handler(json.dumps(query))
+    assert objects(result, "vulnerability")
+    assert get.call_count == 3
+    main_call = get.call_args_list[0]
+    assert main_call.kwargs["timeout"] == 80
+    assert main_call.kwargs["params"] == {
+        "with_linked": "true",
+        "with_comments": "true",
+        "with_bundles": "true",
+        "with_sightings": "true",
+        "with_meta": "true",
+    }
+    assert get.call_args_list[-1].kwargs["params"]["per_page"] == 50
+    assert not any(call.args[0].endswith("/timeline") for call in get.call_args_list)
+
+
+@pytest.mark.parametrize("unset", [None, "", "   "])
+def test_unset_numeric_and_boolean_options_use_defaults(unset):
+    config = dict.fromkeys(vulnerability_lookup.moduleconfig, unset)
+    _, get = run(cve(), config=config, extra_responses=[response({}, 404), response({}, 404)])
+    assert get.call_args_list[0].kwargs["timeout"] == 30
+    assert get.call_args_list[0].kwargs["params"]["with_linked"] == "true"
+    assert get.call_args_list[-1].kwargs["params"]["per_page"] == 50
+
+
+@pytest.mark.parametrize("unset", [None, "", "   "])
+def test_unset_cpe_settings_use_defaults(unset):
+    config = dict.fromkeys(vulnerability_lookup.moduleconfig, unset)
+    result, get = run(
+        {"cvelistv5": [cve()]}, attribute_type="cpe", value="cpe:2.3:a:example:app:*:*:*:*:*:*:*:*", config=config
+    )
+    assert objects(result, "vulnerability")
+    assert get.call_args.kwargs["params"] == {"per_page": 50, "page": 1, "source": "cvelistv5"}
+
+
+@pytest.mark.parametrize("disabled", [False, "false", 0, "0"])
+def test_explicit_false_flags_are_not_replaced_by_defaults(disabled):
+    config = dict.fromkeys(vulnerability_lookup.moduleconfig)
+    config.update({name: disabled for name in vulnerability_lookup.moduleconfig if name.startswith("with_")})
+    _, get = run(cve(), config=config)
+    assert get.call_count == 1
+    assert all(value == "false" for value in get.call_args.kwargs["params"].values())
+
+
+@pytest.mark.parametrize("zero", [0, "0"])
+def test_explicit_zero_related_limit_is_preserved(zero):
+    config = dict.fromkeys(vulnerability_lookup.moduleconfig)
+    config.update({"max_related": zero, "with_epss": False})
+    result, get = run(cve(), config=config)
+    assert objects(result, "vulnerability")
+    assert get.call_count == 1
+
+
 @pytest.mark.parametrize("query", ["invalid", "[]", "null", "{}", '{"attribute": []}'])
 def test_invalid_input_is_an_error(query):
     with patch("requests.get") as get: