https://github.com/python/cpython/commit/8d4286a3f41d36f42c4b4cf5c4451a5a8c23fe87
commit: 8d4286a3f41d36f42c4b4cf5c4451a5a8c23fe87
branch: 3.13
author: Cary Hawkins <[email protected]>
committer: Yhg1s <[email protected]>
date: 2026-10-25T06:30:04-07:00
summary:
[3.13] gh-159428: Don't read mimetypes.knownfiles by default on Windows
(GH-159445) (#159570)
Make knownfiles empty on Windows so that only the registry is used by default.
Files passed to init() or assigned to knownfiles explicitly are still read.
(cherry picked from commit 04a29bf8f9ff8526cd96cb7368400173303a390a)
files:
A Misc/NEWS.d/next/Security/2026-10-15-03-47-08.gh-issue-159428.XHRKwY.rst
M Lib/mimetypes.py
M Lib/test/test_mimetypes.py
diff --git a/Lib/mimetypes.py b/Lib/mimetypes.py
index 3fa9ccf521b12d..047720d3148987 100644
--- a/Lib/mimetypes.py
+++ b/Lib/mimetypes.py
@@ -45,17 +45,23 @@
"suffix_map", "encodings_map", "types_map", "common_types"
]
-knownfiles = [
- "/etc/mime.types",
- "/etc/httpd/mime.types", # Mac OS X
- "/etc/httpd/conf/mime.types", # Apache
- "/etc/apache/mime.types", # Apache 1
- "/etc/apache2/mime.types", # Apache 2
- "/usr/local/etc/httpd/conf/mime.types",
- "/usr/local/lib/netscape/mime.types",
- "/usr/local/etc/httpd/conf/mime.types", # Apache 1.2
- "/usr/local/etc/mime.types", # Apache 1.3
- ]
+if sys.platform == "win32":
+ # The default paths would resolve to the root of the current drive on
Windows
+ # (e.g. C:\etc\mime.types), which unprivileged users can usually create.
+ # Only the registry is used by default.
+ knownfiles = []
+else:
+ knownfiles = [
+ "/etc/mime.types",
+ "/etc/httpd/mime.types", # Mac OS X
+ "/etc/httpd/conf/mime.types", # Apache
+ "/etc/apache/mime.types", # Apache 1
+ "/etc/apache2/mime.types", # Apache 2
+ "/usr/local/etc/httpd/conf/mime.types",
+ "/usr/local/lib/netscape/mime.types",
+ "/usr/local/etc/httpd/conf/mime.types", # Apache 1.2
+ "/usr/local/etc/mime.types", # Apache 1.3
+ ]
inited = False
_db = None
diff --git a/Lib/test/test_mimetypes.py b/Lib/test/test_mimetypes.py
index 54345fed353138..b192021714089a 100644
--- a/Lib/test/test_mimetypes.py
+++ b/Lib/test/test_mimetypes.py
@@ -195,6 +195,10 @@ def test_init_knownfiles(self):
mimetypes.init()
self.assertEqual(guess_file_type("file.test2")[0], "testing/test2")
+ @unittest.skipIf(sys.platform == "win32", "non-Windows only")
+ def test_default_knownfiles(self):
+ self.assertIn("/etc/mime.types", knownfiles)
+
def test_added_types_are_used(self):
mimetypes.add_type('testing/default-type', '')
mime_type, _ = mimetypes.guess_type('')
@@ -431,6 +435,9 @@ def test_registry_parsing(self):
eq(self.db.guess_type("image.jpg"), ("image/jpeg", None))
eq(self.db.guess_type("image.png"), ("image/png", None))
+ def test_default_knownfiles(self):
+ self.assertEqual(knownfiles, [])
+
@unittest.skipIf(not hasattr(_winapi, "_mimetypes_read_windows_registry"),
"read_windows_registry accelerator unavailable")
def test_registry_accelerator(self):
diff --git
a/Misc/NEWS.d/next/Security/2026-10-15-03-47-08.gh-issue-159428.XHRKwY.rst
b/Misc/NEWS.d/next/Security/2026-10-15-03-47-08.gh-issue-159428.XHRKwY.rst
new file mode 100644
index 00000000000000..d481ed2b74a20e
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2026-10-15-03-47-08.gh-issue-159428.XHRKwY.rst
@@ -0,0 +1,2 @@
+:mod:`mimetypes` no longer reads the files listed in
:data:`mimetypes.knownfiles`
+by default on Windows, and uses only the registry.
_______________________________________________
Python-checkins mailing list -- [email protected]
To unsubscribe send an email to [email protected]
https://mail.python.org/mailman3//lists/python-checkins.python.org
Member address: [email protected]
