GHSA-73h3-mf4w-8647

Опубликовано: 22 апр. 2026

Источник: github

Github: Прошло ревью

CVSS4: 0.6

Описание

Poetry has Path Traversal in tar extraction on Python 3.10.0 - 3.10.12 and 3.11.0 - 3.11.4

Summary

The extractall() function in src/poetry/utils/helpers.py:410-426 extracts sdist tarballs without path traversal protection on Python versions where tarfile.data_filter is unavailable. Considering only Python versions which are still supported by Poetry, these are 3.10.0 - 3.10.12 and 3.11.0 - 3.11.4.

Impact

Arbitrary file write (path traversal) from untrusted sdist content.

In practice, the impact is low because an attacker who exploits this vulnerability can as well include arbitrary code in a setup.py, which will be executed when the sdist is built after tar extraction. In other words, a malicious sdist can write arbitrary files by design. However, since it is unexpected and not by design that the file write already happens during tar extraction, this is still considered a vulnerability.

On Python 3.11.2 (Debian Bookworm default, directly tested), a crafted sdist with ../../ tar member paths writes files outside the intended extraction directory. The traversal occurs during metadata resolution (poetry add --lock), before the build backend is run.

Affected Environments:

Python 3.10.0 through 3.10.12 (inclusive): tarfile.data_filter absent or broken
Python 3.11.0 through 3.11.4 (inclusive): tarfile.data_filter absent or broken
Debian Bookworm: Python 3.11.2 (default)
Ubuntu 22.04 LTS: Python 3.10.6 (default)

Patches

Versions 2.3.4 and newer of Poetry ensure that paths are inside the target directory.

Root Cause

File: src/poetry/utils/helpers.py, lines 410-426:

On Python versions without a working tarfile.data_filter, the else branch at line 426 calls tarfile.extractall() without any filter or path validation. This enables three attack vectors:

Direct path traversal: Tar members with ../../ path components write files outside the extraction directory.
Symlink traversal: A symlink member pointing outside dest, followed by a file written through that symlink, escapes the boundary.
Hardlink attacks: Hardlink members can read arbitrary files (same inode) or overwrite targets outside dest.

Call Sites

This function is called from two locations:

src/poetry/installation/chef.py:104 (_prepare_sdist): During poetry install / poetry add when building a package from sdist. Only triggered when the executor is enabled (actual installation).
src/poetry/inspection/info.py:322 (_from_sdist_file): During dependency resolution (poetry lock / poetry add). This path is reached when the sdist's PKG-INFO lacks Requires-Dist metadata, forcing Poetry to extract the archive (and afterwards build the package).

Suggested Fix

Apply path validation in the else branch, covering direct traversal, symlinks, and hardlinks:

def extractall(source: Path, dest: Path, zip: bool) -> None: """Extract all members from either a zip or tar archive.""" if zip: with zipfile.ZipFile(source) as archive: archive.extractall(dest) else: broken_tarfile_filter = {(3, 9, 17), (3, 10, 12), (3, 11, 4)} with tarfile.open(source) as archive: if ( hasattr(tarfile, "data_filter") and sys.version_info[:3] not in broken_tarfile_filter ): archive.extractall(dest, filter="data") else: # Validate all member paths before extraction dest_resolved = dest.resolve() safe_members = [] for member in archive.getmembers(): member_path = (dest_resolved / member.name).resolve() if not member_path.is_relative_to(dest_resolved): raise ValueError( f"Refusing to extract {member.name}: " f"would write outside {dest}" ) if member.issym(): link_target = (member_path.parent / member.linkname).resolve() if not link_target.is_relative_to(dest_resolved): raise ValueError( f"Refusing symlink {member.name}: " f"target {member.linkname} outside {dest}" ) elif member.islnk(): link_target = (dest_resolved / member.linkname).resolve() if not link_target.is_relative_to(dest_resolved): raise ValueError( f"Refusing hardlink {member.name}: " f"target {member.linkname} outside {dest}" ) safe_members.append(member) archive.extractall(dest, members=safe_members)

Ссылки

Пакеты

Наименование

poetry

pip

Затронутые версииВерсия исправления

< 2.3.4

2.3.4

EPSS

Процентиль: 21%

0.00294

Низкий

0.6 Low

CVSS4

CVE ID

CVE-2026-41140

Дефекты

CWE-22

Связанные уязвимости

CVE-2026-41140

CVSS3: 8.7

ubuntu

3 месяца назад

Poetry is a dependency manager for Python. Prior to 2.3.4, the extractall() function in src/poetry/utils/helpers.py:410-426 extracts sdist tarballs without path traversal protection on Python versions where tarfile.data_filter is unavailable. Considering only Python versions which are still supported by Poetry, these are 3.10.0 - 3.10.12 and 3.11.0 - 3.11.4. This vulnerability is fixed in 2.3.4.