diff --git a/superset/utils/date_parser.py b/superset/utils/date_parser.py
index 4fbe79e4728..ba7642990c7 100644
--- a/superset/utils/date_parser.py
+++ b/superset/utils/date_parser.py
@@ -418,9 +418,9 @@ def get_since_until(  # pylint: disable=too-many-arguments,too-many-locals,too-m
     if time_range and separator in time_range:
         time_range_lookup = [
             (
-                r"^(start of|beginning of|end of)\s+"
-                r"(this|last|next|prior)\s+"
-                r"([0-9]+)?\s*"
+                r"^(start of|beginning of|end of)\s{1,5}"
+                r"(this|last|next|prior)\s{1,5}"
+                r"([0-9]+)?\s{0,5}"
                 r"(day|week|month|quarter|year)s?$",  # Matches phrases like "start of next month" # noqa: E501
                 lambda modifier, scope, delta, unit: handle_modifier_and_unit(
                     modifier,
@@ -431,8 +431,8 @@ def get_since_until(  # pylint: disable=too-many-arguments,too-many-locals,too-m
                 ),
             ),
             (
-                r"^(this|last|next|prior)\s+"
-                r"([0-9]+)?\s*"
+                r"^(this|last|next|prior)\s{1,5}"
+                r"([0-9]+)?\s{0,5}"
                 r"(second|minute|day|week|month|quarter|year)s?$",  # Matches "next 5 days" or "last 2 weeks" # noqa: E501
                 lambda scope, delta, unit: handle_scope_and_unit(
                     scope, delta, unit, get_relative_base(unit, relative_start)
diff --git a/tests/unit_tests/utils/date_parser_tests.py b/tests/unit_tests/utils/date_parser_tests.py
index c5e6d512d3a..525c531707c 100644
--- a/tests/unit_tests/utils/date_parser_tests.py
+++ b/tests/unit_tests/utils/date_parser_tests.py
@@ -611,3 +611,50 @@ def test_date_range_migration() -> None:
 
     field = "10 years ago"
     assert not re.search(DateRangeMigration.x_dateunit, field)
+
+
+# Tests for bounded whitespace regex patterns in time_range_lookup
+@pytest.mark.parametrize(
+    "time_range",
+    [
+        "last 7 days : ",
+        "this week : ",
+        "start of next month : ",
+        "prior quarter : ",
+        "last  7 days : ",
+        "last   7 days : ",
+        "last    7 days : ",
+        "last     7 days : ",
+        "start of     next     month : ",  # 5 spaces - valid
+        "last week : ",
+        "last  week : ",
+        "last     week : ",
+        "next 12 months : ",
+        "next  12  months : ",
+        "next     12     months : ",
+        "last 7days : ",  # \s{0,5} allows 0 spaces after number - valid
+    ],
+)
+@patch("superset.utils.date_parser.parse_human_datetime", mock_parse_human_datetime)
+def test_time_range_bounded_whitespace_regex_valid(time_range: str) -> None:
+    """Match expressions with 1-5 spaces between tokens."""
+    result = get_since_until(time_range)
+    assert result[0] is not None, f"Expected '{time_range}' to parse successfully"
+
+
+@pytest.mark.parametrize(
+    "time_range",
+    [
+        "last      7 days : ",
+        "last7days : ",
+        "lastweek : ",
+        "last : ",
+        "start of : ",
+        "last 7 days extra : ",
+    ],
+)
+@patch("superset.utils.date_parser.parse_human_datetime", mock_parse_human_datetime)
+def test_time_range_bounded_whitespace_regex_invalid(time_range: str) -> None:
+    """Reject expressions with 0 or 6+ spaces (fall back to DATETIME wrapping)."""
+    result = get_since_until(time_range)
+    assert result[0] is None, f"Expected '{time_range}' to NOT match bounded regex"