diff --git a/custom_components/myhome/gateway_sessions.py b/custom_components/myhome/gateway_sessions.py
index 5df70c70..8faef4e8 100644
--- a/custom_components/myhome/gateway_sessions.py
+++ b/custom_components/myhome/gateway_sessions.py
@@ -526,7 +526,7 @@ def _is_status_report_item(item: Any) -> bool:
     )
 
 
-_WHO4_QUERY_RE = re.compile(r"^\*#4\*(?P<where>[^#*]+(?:#[^*]+)*)(?:\*(?P<dim>\d+))?##$")
+_WHO4_QUERY_RE = re.compile(r"^\*#4\*(?P<where>[^#*]+(?:#[^#*]+)*)(?:\*(?P<dim>\d+))?##$")
 _WHO4_REPLY_RE = re.compile(
     r"^\*(?:#4\*(?P<dim_where>[^*]+)\*.*|4\*[^*]+\*(?P<act_where>[^*]+))##$"
 )
diff --git a/tests/test_issue_886_myhomeserver1_41_zones.py b/tests/test_issue_886_myhomeserver1_41_zones.py
index 6b6a59eb..0c491928 100644
--- a/tests/test_issue_886_myhomeserver1_41_zones.py
+++ b/tests/test_issue_886_myhomeserver1_41_zones.py
@@ -588,6 +588,15 @@ async def test_pause_status_edge_cases_and_mixed_non_who4_collected_frames(
         _mismatched_who4_reply_zones("*#4*60##", ["*1*1*11##", "*#4*34*0*0146##"])
         == {"34"}
     )
+    # Multi-segment WHERE (`#4#01`) and linear-time rejection of malformed `#`-repeated input (CodeQL py/redos)
+    assert (
+        _mismatched_who4_reply_zones("*#4*60#4#01*60##", ["*#4*34#4#01*60*55##"])
+        == {"34"}
+    )
+    assert (
+        _mismatched_who4_reply_zones("*#4*1" + "#a" * 40 + "!", ["*#4*34*0*0146##"])
+        is None
+    )
 
     scheduler = FrameScheduler()
     try: