{"cve":"CVE-2025-14009","nvd":{"published":"2026-02-18T18:24:19.410","modified":"2026-07-15T02:17:16.703","status":"Modified","description":"A critical vulnerability exists in the NLTK downloader component of nltk/nltk, affecting all versions. The _unzip_iter function in nltk/downloader.py uses zipfile.extractall() without performing path validation or security checks. This allows attackers to craft malicious zip packages that, when downloaded and extracted by NLTK, can execute arbitrary code. The vulnerability arises because NLTK assumes all downloaded packages are trusted and extracts them without validation. If a malicious package contains Python files, such as __init__.py, these files are executed automatically upon import, leading to remote code execution. This issue can result in full system compromise, including file system access, network access, and potential persistence mechanisms.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-94"],"references":["https://huntr.com/bounties/49ecbc02-054e-4470-b2e0-b267936cc4e4","https://access.redhat.com/errata/RHSA-2026:10184","https://access.redhat.com/security/cve/CVE-2025-14009","https://bugzilla.redhat.com/show_bug.cgi?id=2440724","https://huntr.com/bounties/49ecbc02-054e-4470-b2e0-b267936cc4e4"],"products":["nltk:nltk"],"source":"nvd","synced_at":"2026-10-19T22:23:35.260773158+00:00"},"epss":{"cve":"CVE-2025-14009","score":0.01036,"percentile":0.63913,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-7p94-766c-hgjp","url":"https://osv.dev/vulnerability/GHSA-7p94-766c-hgjp","summary":"NLTK has a Zip Slip Vulnerability","modified":"2026-09-10T03:50:34.416389229Z","packages":[{"ecosystem":"PyPI","name":"nltk","purl":"pkg:pypi/nltk","ranges":["<3.9.3"],"fixed":["3.9.3"]}]},{"id":"PYSEC-2026-96","url":"https://osv.dev/vulnerability/PYSEC-2026-96","summary":"","modified":"2026-06-10T17:02:23.646726882Z","packages":[{"ecosystem":"PyPI","name":"nltk","purl":"pkg:pypi/nltk","ranges":["<3.9.3"],"fixed":["3.9.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}