diff --git a/api/extensions/ext_socketio.py b/api/extensions/ext_socketio.py
index 887734c8b8d..78ff7576287 100644
--- a/api/extensions/ext_socketio.py
+++ b/api/extensions/ext_socketio.py
@@ -20,9 +20,14 @@ def _get_ssl_cert_reqs() -> ssl.VerifyMode:
 
 
 def _build_redis_options(redis_url: str) -> dict[str, Any]:
-    """Build Redis options for Socket.IO's cross-process pub/sub manager."""
+    """Build Redis options for Socket.IO's cross-process pub/sub manager.
+
+    Note: ``socket_timeout`` is intentionally omitted. The RedisManager runs a
+    blocking ``pubsub.listen()`` loop that idles indefinitely between messages;
+    applying a read timeout there causes a reconnect storm (issue #39423).
+    ``socket_connect_timeout`` still guards connection establishment.
+    """
     options: dict[str, Any] = {
-        "socket_timeout": dify_config.REDIS_SOCKET_TIMEOUT,
         "socket_connect_timeout": dify_config.REDIS_SOCKET_CONNECT_TIMEOUT,
         "health_check_interval": dify_config.REDIS_HEALTH_CHECK_INTERVAL,
         "protocol": dify_config.REDIS_SERIALIZATION_PROTOCOL,
diff --git a/api/tests/unit_tests/extensions/test_ext_socketio.py b/api/tests/unit_tests/extensions/test_ext_socketio.py
index f9f85106960..20271d1516f 100644
--- a/api/tests/unit_tests/extensions/test_ext_socketio.py
+++ b/api/tests/unit_tests/extensions/test_ext_socketio.py
@@ -31,3 +31,15 @@ def test_build_redis_options_includes_tls_options_for_rediss(monkeypatch) -> Non
     assert options["ssl_ca_certs"] == "/ca.pem"
     assert options["ssl_certfile"] == "/cert.pem"
     assert options["ssl_keyfile"] == "/key.pem"
+
+
+def test_build_redis_options_omits_socket_timeout(monkeypatch) -> None:
+    # socket_timeout must not be passed to RedisManager because the pub/sub
+    # listen loop blocks indefinitely between messages; a read timeout there
+    # triggers an infinite reconnect storm (issue #39423).
+    monkeypatch.setattr(ext_socketio.dify_config, "REDIS_SOCKET_TIMEOUT", 5.0)
+
+    options = ext_socketio._build_redis_options("redis://redis.example.com:6380/3")
+
+    assert "socket_timeout" not in options
+    assert "socket_connect_timeout" in options