CVE-2026-59974

Path traversal in stanza unzip allows arbitrary file overwrite

• CVSS 7.8
• 22
• Input Validation and Sanitization
• Remote

Stanza is a Stanford NLP Python library for tokenization, sentence segmentation, NER, and parsing of many human languages. Prior to 1.14.0, stanza.resources.common.unzip in stanza/resources/common.py passes downloaded model and resource archives to zipfile.ZipFile.extractall without validating member paths, and the vulnerable extraction path is reachable through stanza.download and stanza.install_corenlp. A malicious archive containing parent-directory traversal entries can write outside the intended model directory, allowing files writable by the Stanza process to be overwritten and potentially enabling code execution through modified shell configuration, SSH authorization data, Python packages, or executable scripts. This issue is fixed in version 1.14.0.

CVE

CVE-2026-59974

CWE

22

CVSS base score

7.8

Published

2026-09-16

OWASP

A04 Insecure Design

Orthogonal defect classification

Checking

Code defect classification

Missing Check

Category

Input Validation and Sanitization

Subcategory

Path Traversal

Accessibility scope

Remote

Impact

Arbitrary Code Execution

Affected component

Stanza

Fixed by upgrading

Yes

Solution

Upgrade Stanza to version 1.14.0 or newer.

import os
import zipfile

def unzip_archive(archive_path, target_dir):
    """Extract a zip archive to target_dir without path validation."""
    with zipfile.ZipFile(archive_path, 'r') as zip_ref:
        # VULNERABLE: unsafe extractall allows path traversal
        zip_ref.extractall(target_dir)

import os
import zipfile

def unzip_archive(archive_path, target_dir):
    """Extract a zip archive to target_dir with path validation."""
    with zipfile.ZipFile(archive_path, 'r') as zip_ref:
        # FIX: validate member paths to prevent traversal
        for member in zip_ref.infolist():
            member_path = os.path.normpath(os.path.join(target_dir, member.filename))
            if not member_path.startswith(os.path.abspath(target_dir) + os.sep):
                raise Exception("Unsafe path detected in zip entry")
        zip_ref.extractall(target_dir)

__VAITP_MODEL_REFUSED__

@misc{vaitp:cve202659974,
  title        = {{Path traversal in stanza unzip allows arbitrary file overwrite}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2026},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2026-59974},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2026-59974/}}
}