---
id: CVE-2026-62388
title: >-
  NLTK versions before 3.10.0 default to ENFORCE=False in pathsec.py, causing
  all security validation functions to emit warnings instead of raising
  exceptions
summary: >-
  NLTK versions before 3.10.0 default to ENFORCE=False in pathsec.py, causing
  all security validation functions to emit warnings instead of raising
  exceptions. Attackers can bypass path traversal and pickle deserialization
  protections by e…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-1188
vendor: nltk
product: nltk
affected:
  - nltk < 3.10.0
patched:
  - nltk 3.10.0
published: '2026-08-22'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-62388'
references:
  - url: 'https://github.com/nltk/nltk/security/advisories/GHSA-p3m8-78j2-g5p3'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/nltk-before-insecure-default-configuration-pathsec
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nltk/nltk/security/advisories/GHSA-p3m8-78j2-g5p3'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-62388.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-62388'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2521328'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-62388'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-62388'
  - url: 'https://github.com/nltk/nltk/pull/3593'
  - url: >-
      https://github.com/nltk/nltk/commit/155e40343cff0bf50d233e274a12e04d1428b1d9
  - url: 'https://github.com/nltk/nltk/releases/tag/v3.10.0'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3722.yaml
  - url: 'https://github.com/advisories/GHSA-p3m8-78j2-g5p3'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - ghsa
  - pip
epss: 0.00512
epssPercentile: 0.43493
ingestedAt: '2026-08-23T04:42:15.239Z'
aliases:
  - GHSA-p3m8-78j2-g5p3
ecosystem: pip
---

## Overview

NLTK versions before 3.10.0 default to ENFORCE=False in pathsec.py, causing all security validation functions to emit warnings instead of raising exceptions. Attackers can bypass path traversal and pickle deserialization protections by exploiting the disabled security controls that are only active when manually enabled.

## Affected

- `nltk < 3.10.0`

## Remediation

Upgrade past the affected range:

- `nltk 3.10.0`

## Vendor advisories

- **Red Hat VEX** · Important · affected: Lightspeed Core, Red Hat Ansible Automation Platform 2 · no fix planned: Red Hat Ansible Automation Platform 2, Lightspeed Core · updated 2026-10-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-62388.json)

## Package advisory (CVE-2026-62388)

Affected packages:

- `nltk <= 3.9.4`

Patched in:

- `nltk 3.10.0`

Source: https://github.com/advisories/GHSA-p3m8-78j2-g5p3