diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6b5363d..06aa1e3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -69,6 +69,9 @@ under **Unreleased** until a new version is selected and published.
 
 ### Fixed
 
+- Rejected non-finite Doris HTTP timeout configuration and restored safe
+  timeout defaults at the client boundary, preventing NaN values from
+  disabling the total request deadline.
 - Preserved fail-closed distribution provenance across version parsing,
   brandless FE/BE component fallback, and certification evidence validation,
   preventing unknown or mismatched brands from inheriting Apache Doris
diff --git a/doris_mcp_server/utils/config.py b/doris_mcp_server/utils/config.py
index 7646365..a37b0dd 100644
--- a/doris_mcp_server/utils/config.py
+++ b/doris_mcp_server/utils/config.py
@@ -22,6 +22,7 @@
 
 import json
 import logging
+import math
 import multiprocessing
 import os
 import secrets
@@ -2252,14 +2253,23 @@ def validate(self) -> list[str]:
         if not (1 <= self.database.be_webserver_port <= 65535):
             errors.append("Doris BE HTTP port must be in the range 1-65535")
 
-        if self.database.http_connect_timeout_seconds <= 0:
-            errors.append("Doris HTTP connect timeout must be greater than 0")
+        if (
+            not math.isfinite(self.database.http_connect_timeout_seconds)
+            or self.database.http_connect_timeout_seconds <= 0
+        ):
+            errors.append("Doris HTTP connect timeout must be finite and greater than 0")
 
-        if self.database.http_read_timeout_seconds <= 0:
-            errors.append("Doris HTTP read timeout must be greater than 0")
+        if (
+            not math.isfinite(self.database.http_read_timeout_seconds)
+            or self.database.http_read_timeout_seconds <= 0
+        ):
+            errors.append("Doris HTTP read timeout must be finite and greater than 0")
 
-        if self.database.http_total_timeout_seconds <= 0:
-            errors.append("Doris HTTP total timeout must be greater than 0")
+        if (
+            not math.isfinite(self.database.http_total_timeout_seconds)
+            or self.database.http_total_timeout_seconds <= 0
+        ):
+            errors.append("Doris HTTP total timeout must be finite and greater than 0")
 
         if self.database.http_max_response_bytes <= 0:
             errors.append("Doris HTTP response byte limit must be greater than 0")
diff --git a/doris_mcp_server/utils/doris_http_client.py b/doris_mcp_server/utils/doris_http_client.py
index 41c0a26..2e89021 100644
--- a/doris_mcp_server/utils/doris_http_client.py
+++ b/doris_mcp_server/utils/doris_http_client.py
@@ -20,6 +20,7 @@
 
 import asyncio
 import ipaddress
+import math
 import socket
 from collections.abc import Mapping
 from dataclasses import dataclass
@@ -168,7 +169,7 @@ def _bounded_float(value: Any, default: float) -> float:
         parsed = float(value)
     except (TypeError, ValueError):
         return default
-    if parsed <= 0:
+    if not math.isfinite(parsed) or parsed <= 0:
         return default
     return min(parsed, MAX_TIMEOUT_SECONDS)
 
diff --git a/test/security/test_doris_http_ssrf.py b/test/security/test_doris_http_ssrf.py
index 20977b0..7824570 100644
--- a/test/security/test_doris_http_ssrf.py
+++ b/test/security/test_doris_http_ssrf.py
@@ -300,6 +300,61 @@ async def test_read_and_total_timeouts_are_enforced() -> None:
             )
 
 
+@pytest.mark.parametrize(
+    ("setting", "label"),
+    [
+        ("DORIS_HTTP_CONNECT_TIMEOUT_SECONDS", "connect"),
+        ("DORIS_HTTP_READ_TIMEOUT_SECONDS", "read"),
+        ("DORIS_HTTP_TOTAL_TIMEOUT_SECONDS", "total"),
+    ],
+)
+@pytest.mark.parametrize("value", ["nan", "inf", "-inf", "1e309"])
+def test_http_timeout_configuration_rejects_non_finite_values(
+    monkeypatch: pytest.MonkeyPatch,
+    setting: str,
+    label: str,
+    value: str,
+) -> None:
+    monkeypatch.setenv(setting, value)
+    config = DorisConfig.from_env()
+    assert any(
+        error.startswith(f"Doris HTTP {label} timeout")
+        for error in config.validate()
+    )
+
+
+@pytest.mark.parametrize("value", [float("nan"), float("inf"), float("-inf")])
+def test_http_client_uses_safe_defaults_for_non_finite_timeouts(value: float) -> None:
+    client = _http_client(
+        "127.0.0.1",
+        8030,
+        connect_timeout=value,
+        read_timeout=value,
+        total_timeout=value,
+    )
+    assert client.connect_timeout_seconds == doris_http_client_module.DEFAULT_CONNECT_TIMEOUT_SECONDS
+    assert client.read_timeout_seconds == doris_http_client_module.DEFAULT_READ_TIMEOUT_SECONDS
+    assert client.total_timeout_seconds == doris_http_client_module.DEFAULT_TOTAL_TIMEOUT_SECONDS
+
+
+async def test_nan_total_timeout_cannot_disable_the_http_deadline(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr(doris_http_client_module, "DEFAULT_TOTAL_TIMEOUT_SECONDS", 0.05)
+    async with _http_server(body=b"ok", delay_seconds=0.2) as port:
+        client = _http_client("127.0.0.1", port, total_timeout=float("nan"))
+        with pytest.raises(DorisHTTPRequestError, match="timed out"):
+            await asyncio.wait_for(
+                client.get(
+                    role="fe",
+                    host="127.0.0.1",
+                    port=port,
+                    path="/metrics",
+                ),
+                timeout=1,
+            )
+
+
 async def test_monitoring_does_not_discover_be_http_nodes_from_sql() -> None:
     manager = _manager(
         _database_config(