diff --git a/src/xhs_archive/cli.py b/src/xhs_archive/cli.py
index 2cbe927..e48890d 100644
--- a/src/xhs_archive/cli.py
+++ b/src/xhs_archive/cli.py
@@ -12,6 +12,7 @@
 from pathlib import Path
 from difflib import SequenceMatcher
 from typing import Annotated
+from urllib.parse import urlsplit
 
 import typer
 from PIL import Image, ImageStat
@@ -33,6 +34,7 @@
 from .utils import write_json
 
 app = typer.Typer(no_args_is_help=True)
+_ALLOWED_BOARD_HOSTS = frozenset({"xiaohongshu.com", "www.xiaohongshu.com"})
 
 
 def _json(data: object) -> None:
@@ -59,29 +61,55 @@ def _module_importable(name: str) -> bool:
     return importlib.util.find_spec(name) is not None
 
 
+def _validated_board_url(value: str) -> str:
+    candidate = value.strip()
+    try:
+        parsed = urlsplit(candidate)
+        hostname = (parsed.hostname or "").rstrip(".").lower()
+        port = parsed.port
+    except ValueError as exc:
+        raise typer.BadParameter("收藏专辑 URL 无效。") from exc
+    if (
+        parsed.scheme != "https"
+        or hostname not in _ALLOWED_BOARD_HOSTS
+        or parsed.username is not None
+        or parsed.password is not None
+        or port not in {None, 443}
+        or not parsed.path.startswith("/board/")
+    ):
+        raise typer.BadParameter("收藏专辑 URL 必须是 https://www.xiaohongshu.com/board/...。")
+    return candidate
+
+
 def _resolve_board_url(board_url: str | None) -> str:
     if board_url:
-        return board_url
+        return _validated_board_url(board_url)
     env_url = os.environ.get("XHS_BOARD_URL")
     if env_url:
-        return env_url
+        return _validated_board_url(env_url)
     paste = _run_command(["/usr/bin/pbpaste"])
-    if paste and "xiaohongshu.com" in paste:
-        return paste.strip()
+    if paste:
+        try:
+            return _validated_board_url(paste)
+        except typer.BadParameter:
+            pass
     raise typer.BadParameter("缺少收藏专辑 URL：请设置 XHS_BOARD_URL 或传入 --board-url。")
 
 
+def _path_is_within(candidate: str, root: str) -> bool:
+    normalized_candidate = os.path.normcase(os.path.normpath(candidate))
+    normalized_root = os.path.normcase(os.path.normpath(root))
+    try:
+        return os.path.commonpath([normalized_candidate, normalized_root]) == normalized_root
+    except ValueError:
+        return False
+
+
 @app.command()
 def doctor(json_output: Annotated[bool, typer.Option("--json", help="Output JSON.")] = False) -> None:
     cfg = load_config()
     conda_prefix = os.environ.get("CONDA_PREFIX")
-    sys_prefix = Path(sys.prefix).resolve()
-    conda_active = False
-    if conda_prefix:
-        try:
-            conda_active = sys_prefix.is_relative_to(Path(conda_prefix).resolve())
-        except Exception:
-            conda_active = False
+    conda_active = bool(conda_prefix and _path_is_within(sys.prefix, conda_prefix))
     paddle_importable = _module_importable("paddle")
     paddle_device = None
     if paddle_importable:
diff --git a/tests/test_cli.py b/tests/test_cli.py
new file mode 100644
index 0000000..87bbb74
--- /dev/null
+++ b/tests/test_cli.py
@@ -0,0 +1,37 @@
+import pytest
+import typer
+
+from xhs_archive.cli import _path_is_within, _validated_board_url
+
+
+@pytest.mark.parametrize(
+    "url",
+    [
+        "https://www.xiaohongshu.com/board/demo",
+        "https://xiaohongshu.com/board/b/demo?tab=notes",
+        "https://www.xiaohongshu.com.:443/board/demo",
+    ],
+)
+def test_validated_board_url_accepts_expected_hosts(url: str) -> None:
+    assert _validated_board_url(f"  {url}  ") == url
+
+
+@pytest.mark.parametrize(
+    "url",
+    [
+        "http://www.xiaohongshu.com/board/demo",
+        "https://www.xiaohongshu.com.evil.example/board/demo",
+        "https://www.xiaohongshu.com@evil.example/board/demo",
+        "https://www.xiaohongshu.com/explore/demo",
+        "not-a-url-containing-xiaohongshu.com",
+    ],
+)
+def test_validated_board_url_rejects_untrusted_urls(url: str) -> None:
+    with pytest.raises(typer.BadParameter):
+        _validated_board_url(url)
+
+
+def test_path_is_within_uses_path_boundaries() -> None:
+    assert _path_is_within("/opt/conda/envs/archive", "/opt/conda")
+    assert _path_is_within("/opt/conda", "/opt/conda")
+    assert not _path_is_within("/opt/conda-evil/envs/archive", "/opt/conda")