diff --git a/babel/localedata.py b/babel/localedata.py

index 4b6d3b6..080b723 100644

--- a/babel/localedata.py

+++ b/babel/localedata.py

@@ -13,6 +13,8 @@

 """

 import os

+import re

+import sys

 import threading

 from collections import MutableMapping

 from itertools import chain

@@ -33,6 +35,7 @@ def get_base_dir():

 _cache = {}

 _cache_lock = threading.RLock()

 _dirname = os.path.join(get_base_dir(), 'locale-data')

+_windows_reserved_name_re = re.compile("^(con|prn|aux|nul|com[0-9]|lpt[0-9])$", re.I)

 def normalize_locale(name):

@@ -49,6 +52,22 @@ def normalize_locale(name):

             return locale_id

+def resolve_locale_filename(name):

+    """

+    Resolve a locale identifier to a `.dat` path on disk.

+    """

+

+    # Clean up any possible relative paths.

+    name = os.path.basename(name)

+

+    # Ensure we're not left with one of the Windows reserved names.

+    if sys.platform == "win32" and _windows_reserved_name_re.match(os.path.splitext(name)[0]):

+        raise ValueError("Name %s is invalid on Windows" % name)

+

+    # Build the path.

+    return os.path.join(_dirname, '%s.dat' % name)

+

+

 def exists(name):

     """Check whether locale data is available for the given locale.

@@ -60,7 +79,7 @@ def exists(name):

         return False

     if name in _cache:

         return True

-    file_found = os.path.exists(os.path.join(_dirname, '%s.dat' % name))

+    file_found = os.path.exists(resolve_locale_filename(name))

     return True if file_found else bool(normalize_locale(name))

@@ -102,6 +121,7 @@ def load(name, merge_inherited=True):

     :raise `IOError`: if no locale data file is found for the given locale

                       identifer, or one of the locales it inherits from

     """

+    name = os.path.basename(name)

     _cache_lock.acquire()

     try:

         data = _cache.get(name)

@@ -119,7 +139,7 @@ def load(name, merge_inherited=True):

                     else:

                         parent = '_'.join(parts[:-1])

                 data = load(parent).copy()

-            filename = os.path.join(_dirname, '%s.dat' % name)

+            filename = resolve_locale_filename(name)

             with open(filename, 'rb') as fileobj:

                 if name != 'root' and merge_inherited:

                     merge(data, pickle.load(fileobj))

diff --git a/tests/test_localedata.py b/tests/test_localedata.py

index 3599b21..173e7a3 100644

--- a/tests/test_localedata.py

+++ b/tests/test_localedata.py

@@ -11,12 +11,18 @@

 # individuals. For the exact contribution history, see the revision

 # history and logs, available at http://babel.edgewall.org/log/.

+import os

+import pickle

+import sys

+import tempfile

 import unittest

 import random

 from operator import methodcaller

 import sys

-from babel import localedata, numbers

+import pytest

+

+from babel import localedata, Locale, UnknownLocaleError, numbers

 class MergeResolveTestCase(unittest.TestCase):

@@ -117,3 +123,33 @@ def test_locale_argument_acceptance():

     assert normalized_locale == None

     locale_exist = localedata.exists(['en_us', None])

     assert locale_exist == False

+

+def test_locale_name_cleanup():

+    """

+    Test that locale identifiers are cleaned up to avoid directory traversal.

+    """

+    no_exist_name = os.path.join(tempfile.gettempdir(), "babel%d.dat" % random.randint(1, 99999))

+    with open(no_exist_name, "wb") as f:

+        pickle.dump({}, f)

+

+    try:

+        name = os.path.splitext(os.path.relpath(no_exist_name, localedata._dirname))[0]

+    except ValueError:

+        if sys.platform == "win32":

+            pytest.skip("unable to form relpath")

+        raise

+

+    assert not localedata.exists(name)

+    with pytest.raises(IOError):

+        localedata.load(name)

+    with pytest.raises(UnknownLocaleError):

+        Locale(name)

+

+

+@pytest.mark.skipif(sys.platform != "win32", reason="windows-only test")

+def test_reserved_locale_names():

+    for name in ("con", "aux", "nul", "prn", "com8", "lpt5"):

+        with pytest.raises(ValueError):

+            localedata.load(name)

+        with pytest.raises(ValueError):

+            Locale(name)