https://github.com/python/cpython/commit/30ac23e3e413c2d38b80691b1c80e3cd74a22639
commit: 30ac23e3e413c2d38b80691b1c80e3cd74a22639
branch: main
author: Harjoth Khara <[email protected]>
committer: serhiy-storchaka <[email protected]>
date: 2026-08-04T19:47:02+03:00
summary:
gh-117807: Handle invalid UTF-8 in mimetypes map files (GH-151216)
files:
A Misc/NEWS.d/next/Library/2026-06-10-00-00-01.gh-issue-117807.Cx1178.rst
M Lib/mimetypes.py
M Lib/test/test_mimetypes.py
diff --git a/Lib/mimetypes.py b/Lib/mimetypes.py
index 4339ef5a61397d..1d6b33fe854c94 100644
--- a/Lib/mimetypes.py
+++ b/Lib/mimetypes.py
@@ -250,7 +250,7 @@ def read(self, filename, strict=True):
list of standard types, else to the list of non-standard
types.
"""
- with open(filename, encoding='utf-8') as fp:
+ with open(filename, encoding='utf-8', errors='surrogateescape') as fp:
self.readfp(fp, strict)
def readfp(self, fp, strict=True):
@@ -444,7 +444,7 @@ def init(files=None):
def read_mime_types(file):
try:
- f = open(file, encoding='utf-8')
+ f = open(file, encoding='utf-8', errors='surrogateescape')
except OSError:
return None
with f:
diff --git a/Lib/test/test_mimetypes.py b/Lib/test/test_mimetypes.py
index 19983fa3fa7628..1e0f6664af0d06 100644
--- a/Lib/test/test_mimetypes.py
+++ b/Lib/test/test_mimetypes.py
@@ -67,9 +67,50 @@ def test_read_mime_types(self):
with unittest.mock.patch.object(mimetypes, 'open',
return_value=fp) as mock_open:
mime_dict = mimetypes.read_mime_types(filename)
- mock_open.assert_called_with(filename, encoding='utf-8')
+ mock_open.assert_called_with(filename, encoding='utf-8',
+ errors='surrogateescape')
eq(mime_dict[".Français"], "application/no-mans-land")
+ def test_read_mime_types_invalid_utf8_comment(self):
+ with os_helper.temp_dir() as directory:
+ data = (b"# non-UTF-8 comment: \x83\n"
+ b"x-application/x-unittest pyunit\n")
+ file = os.path.join(directory, "sample.mimetype")
+ with open(file, "wb") as f:
+ f.write(data)
+
+ mime_dict = mimetypes.read_mime_types(file)
+ self.assertEqual(
+ mime_dict[".pyunit"], "x-application/x-unittest")
+
+ db = mimetypes.MimeTypes()
+ db.read(file)
+ self.assertEqual(
+ db.guess_file_type("sample.pyunit")[0],
+ "x-application/x-unittest")
+
+ mimetypes.init(files=[file])
+ self.assertEqual(
+ mimetypes.guess_file_type("sample.pyunit")[0],
+ "x-application/x-unittest")
+
+ def test_read_mime_types_invalid_utf8_type(self):
+ # A non-UTF-8 byte in a type or extension (not only in a comment) is
+ # preserved via surrogateescape, so the mapping is not corrupted.
+ with os_helper.temp_dir() as directory:
+ data = (b"x-application/x-unittest pyunit\n"
+ b"application/bad\x83 badext\x83\n")
+ file = os.path.join(directory, "sample.mimetype")
+ with open(file, "wb") as f:
+ f.write(data)
+
+ bad_type = b"application/bad\x83".decode("utf-8",
"surrogateescape")
+ bad_ext = b".badext\x83".decode("utf-8", "surrogateescape")
+
+ mime_dict = mimetypes.read_mime_types(file)
+ self.assertEqual(mime_dict[".pyunit"], "x-application/x-unittest")
+ self.assertEqual(mime_dict[bad_ext], bad_type)
+
def test_init_reinitializes(self):
# Issue 4936: make sure an init starts clean
# First, put some poison into the types table
diff --git
a/Misc/NEWS.d/next/Library/2026-06-10-00-00-01.gh-issue-117807.Cx1178.rst
b/Misc/NEWS.d/next/Library/2026-06-10-00-00-01.gh-issue-117807.Cx1178.rst
new file mode 100644
index 00000000000000..d6a874a84867a2
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-06-10-00-00-01.gh-issue-117807.Cx1178.rst
@@ -0,0 +1,2 @@
+Fix :mod:`mimetypes` initialization from MIME map files containing invalid
+UTF-8 bytes.
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