[5.1.x] Fixed CVE-2025-59682 -- Fixed potential partial directory-traversal via archive.extract().

Thanks stackered for the report.

Follow up to 05413af.

Backport of 924a0c0 from main.

Author: sarahboyce

django/utils/archive.py

@@ -145,7 +145,11 @@ def has_leading_dir(self, paths):
     def target_filename(self, to_path, name):
         target_path = os.path.abspath(to_path)
         filename = os.path.abspath(os.path.join(target_path, name))
-        if not filename.startswith(target_path):
+        try:
+            if os.path.commonpath([target_path, filename]) != target_path:
+                raise SuspiciousOperation("Archive contains invalid path: '%s'" % name)
+        except ValueError:
+            # Different drives on Windows raises ValueError.
             raise SuspiciousOperation("Archive contains invalid path: '%s'" % name)
         return filename
 

docs/releases/4.2.25.txt

@@ -15,3 +15,11 @@ CVE-2025-59681: Potential SQL injection in ``QuerySet.annotate()``, ``alias()``,
 to SQL injection in column aliases, using a suitably crafted dictionary, with
 dictionary expansion, as the ``**kwargs`` passed to these methods (follow up to
 :cve:`2022-28346`).
+
+CVE-2025-59682: Potential partial directory-traversal via ``archive.extract()``
+===============================================================================
+
+The ``django.utils.archive.extract()`` function, used by
+:option:`startapp --template` and :option:`startproject --template`, allowed
+partial directory-traversal via an archive with file paths sharing a common
+prefix with the target directory (follow up to :cve:`2021-3281`).

docs/releases/5.1.13.txt

@@ -15,3 +15,11 @@ CVE-2025-59681: Potential SQL injection in ``QuerySet.annotate()``, ``alias()``,
 to SQL injection in column aliases, using a suitably crafted dictionary, with
 dictionary expansion, as the ``**kwargs`` passed to these methods (follow up to
 :cve:`2022-28346`).
+
+CVE-2025-59682: Potential partial directory-traversal via ``archive.extract()``
+===============================================================================
+
+The ``django.utils.archive.extract()`` function, used by
+:option:`startapp --template` and :option:`startproject --template`, allowed
+partial directory-traversal via an archive with file paths sharing a common
+prefix with the target directory (follow up to :cve:`2021-3281`).

tests/utils_tests/test_archive.py

@@ -3,6 +3,7 @@
 import sys
 import tempfile
 import unittest
+import zipfile
 
 from django.core.exceptions import SuspiciousOperation
 from django.test import SimpleTestCase
@@ -94,3 +95,21 @@ def test_extract_function_traversal(self):
             with self.subTest(entry), tempfile.TemporaryDirectory() as tmpdir:
                 with self.assertRaisesMessage(SuspiciousOperation, msg % invalid_path):
                     archive.extract(os.path.join(archives_dir, entry), tmpdir)
+
+    def test_extract_function_traversal_startswith(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            base = os.path.abspath(tmpdir)
+            tarfile_handle = tempfile.NamedTemporaryFile(suffix=".zip", delete=False)
+            tar_path = tarfile_handle.name
+            tarfile_handle.close()
+            self.addCleanup(os.remove, tar_path)
+
+            malicious_member = os.path.join(base + "abc", "evil.txt")
+            with zipfile.ZipFile(tar_path, "w") as zf:
+                zf.writestr(malicious_member, "evil\n")
+                zf.writestr("test.txt", "data\n")
+
+            with self.assertRaisesMessage(
+                SuspiciousOperation, "Archive contains invalid path"
+            ):
+                archive.extract(tar_path, base)