From 24ab89cdacfa68857b4c7b5fb5234a75193dc941 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20Gr=C3=B6nholm?= <alex.gronholm@nextday.fi>
Date: Thu, 22 Jan 2026 01:41:14 +0200
Subject: [PATCH] Fixed security issue around wheel unpack (#675)

A maliciously crafted wheel could cause the permissions of a file outside the unpack tree to be altered.

Fixes CVE-2026-24049.

(cherry picked from commit 7a7d2de96b22a9adf9208afcc9547e1001569fef)
---
 docs/news.rst            |  5 +++++
 src/wheel/cli/unpack.py  |  4 ++--
 tests/cli/test_unpack.py | 23 +++++++++++++++++++++++
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/docs/news.rst b/docs/news.rst
index 9e5488a..1033520 100644
--- a/docs/news.rst
+++ b/docs/news.rst
@@ -1,6 +1,11 @@
 Release Notes
 =============
 
+**BACKPORTS**
+
+- Fixed ``wheel unpack`` potentially altering the permissions of files outside of the
+  destination tree with maliciously crafted wheels (CVE-2026-24049)
+
 **0.41.2 (2023-08-22)**
 
 - Fixed platform tag detection for GraalPy and 32-bit python running on an aarch64
diff --git a/src/wheel/cli/unpack.py b/src/wheel/cli/unpack.py
index d48840e..83dc742 100644
--- a/src/wheel/cli/unpack.py
+++ b/src/wheel/cli/unpack.py
@@ -19,12 +19,12 @@ def unpack(path: str, dest: str = ".") -> None:
         destination = Path(dest) / namever
         print(f"Unpacking to: {destination}...", end="", flush=True)
         for zinfo in wf.filelist:
-            wf.extract(zinfo, destination)
+            target_path = Path(wf.extract(zinfo, destination))
 
             # Set permissions to the same values as they were set in the archive
             # We have to do this manually due to
             # https://github.com/python/cpython/issues/59999
             permissions = zinfo.external_attr >> 16 & 0o777
-            destination.joinpath(zinfo.filename).chmod(permissions)
+            target_path.chmod(permissions)
 
     print("OK")
diff --git a/tests/cli/test_unpack.py b/tests/cli/test_unpack.py
index ae584af..951ba29 100644
--- a/tests/cli/test_unpack.py
+++ b/tests/cli/test_unpack.py
@@ -34,3 +34,26 @@ def test_unpack_executable_bit(tmp_path):
     unpack(str(wheel_path), str(tmp_path))
     assert not script_path.is_dir()
     assert stat.S_IMODE(script_path.stat().st_mode) == 0o755
+
+
+@pytest.mark.skipif(
+    platform.system() == "Windows", reason="Windows does not support chmod()"
+)
+def test_chmod_outside_unpack_tree(tmp_path_factory: TempPathFactory) -> None:
+    wheel_path = tmp_path_factory.mktemp("build") / "test-1.0-py3-none-any.whl"
+    with WheelFile(wheel_path, "w") as wf:
+        wf.writestr(
+            "test-1.0.dist-info/METADATA",
+            "Metadata-Version: 2.4\nName: test\nVersion: 1.0\n",
+        )
+        wf.writestr("../../system-file", b"malicious data")
+
+    extract_root_path = tmp_path_factory.mktemp("extract")
+    system_file = extract_root_path / "system-file"
+    extract_path = extract_root_path / "subdir"
+    system_file.write_bytes(b"important data")
+    system_file.chmod(0o755)
+    unpack(str(wheel_path), str(extract_path))
+
+    assert system_file.read_bytes() == b"important data"
+    assert stat.S_IMODE(system_file.stat().st_mode) == 0o755
-- 
2.52.0