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CVE-2026-54293

CVE-2026-54293 · NLTK: URL-Encoded Path Traversal in nltk.data.load() Allows Arbitrary Local File Read

This page contains facts from public vulnerability sources. Check the original advisory before updating.

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. Prior to 3.10.0-rc1, nltk.data.load() in NLTK is vulnerable to path traversal via URL-encoded path separators and traversal segments when using the nltk: URL scheme. The unsafe-path regex check is performed before url2pathname() decodes the %xx sequences (a classic decode-after-check / TOCTOU-style flaw), allowing an attacker to bypass the protection documented in NLTK's SECURITY.md and read arbitrary files from the filesystem. While literal traversal strings such as ../../../etc/passwd are correctly blocked, encoded variants such as %2fetc%2fpasswd, %2e%2e%2f..., and ..%2f..%2f slip past the regex and are subsequently decoded into a real filesystem path. This vulnerability is fixed in 3.10.0-rc1.

CVSS 7.5 · High · EPSS 0.6% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • nltk

    Versions
    • < 3.10.0-rc1: Affected

    No fix published

  • nltk Debian:12

    Versions
    • 3.10.0-1
    • 3.10.1-1
    • 3.10.3-1
    • 3.8-1
    • 3.8.1-1
    • 3.9.1-1
    • 3.9.1-2
    • 3.9.2-1
    • 3.9.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Debian:13

    Versions
    • 3.10.0-1
    • 3.10.1-1
    • 3.10.3-1
    • 3.9.1-2
    • 3.9.2-1
    • 3.9.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Debian:14

    Versions
    • 3.9.1-2
    • 3.9.2-1
    • 3.9.3-1
    Affected ranges
    • ECOSYSTEM: < 3.10.0-1

    Update to 3.10.0-1

  • nltk PyPI

    Versions
    • 0.8
    • 0.9
    • 0.9.3
    • 0.9.4
    • 0.9.5
    • 0.9.6
    • 0.9.7
    • 0.9.8
    • 0.9.9
    • 2.0.1
    • 2.0.1rc1
    • 2.0.1rc2-git
    • 2.0.1rc3
    • 2.0.1rc4
    • 2.0.2
    • 2.0.3
    • 2.0.4
    • 2.0.5
    • 2.0b4
    • 2.0b5
    • 2.0b6
    • 2.0b7
    • 2.0b8
    • 2.0b9
    • 3.0.0
    • 3.0.0b1
    • 3.0.0b2
    • 3.0.1
    • 3.0.2
    • 3.0.3
    • 3.0.4
    • 3.0.5
    • 3.1
    • 3.2
    • 3.2.1
    • 3.2.2
    • 3.2.3
    • 3.2.4
    • 3.2.5
    • 3.3
    • 3.4
    • 3.4.1
    • 3.4.2
    • 3.4.3
    • 3.4.4
    • 3.4.5
    • 3.5
    • 3.5b1
    • 3.6
    • 3.6.1
    • 3.6.2
    • 3.6.3
    • 3.6.4
    • 3.6.5
    • 3.6.6
    • 3.6.7
    • 3.7
    • 3.8
    • 3.8.1
    • 3.9
    • 3.9.1
    • 3.9.2
    • 3.9.3
    • 3.9.4
    • 3.9b1
    Affected ranges
    • ECOSYSTEM: < 3.10.0

    Update to 3.10.0

  • nltk Ubuntu:Pro:14.04:LTS

    Versions
    • 2.0~b9-0ubuntu4
    • 2.0~b9-0ubuntu4.1~esm2
    • 2.0~b9-0ubuntu4.1~esm4
    • 2.0~b9-0ubuntu4.1~esm5
    • 2.0~b9-0ubuntu4.1~esm6
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Ubuntu:Pro:16.04:LTS

    Versions
    • 3.0.4-1
    • 3.0.5-1
    • 3.1-1
    • 3.1-1ubuntu0.1
    • 3.1-1ubuntu0.1+esm1
    • 3.1-1ubuntu0.1+esm2
    • 3.1-1ubuntu0.1+esm3
    • 3.1-1ubuntu0.1+esm4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Ubuntu:Pro:18.04:LTS

    Versions
    • 3.2.4-1
    • 3.2.5-1
    • 3.2.5-1ubuntu0.1
    • 3.2.5-1ubuntu0.1+esm1
    • 3.2.5-1ubuntu0.1+esm2
    • 3.2.5-1ubuntu0.1+esm3
    • 3.2.5-1ubuntu0.1+esm4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Ubuntu:Pro:20.04:LTS

    Versions
    • 3.4.5-1
    • 3.4.5-2
    • 3.4.5-2ubuntu0.1~esm1
    • 3.4.5-2ubuntu0.1~esm2
    • 3.4.5-2ubuntu0.1~esm3
    • 3.4.5-2ubuntu0.1~esm4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Ubuntu:Pro:22.04:LTS

    Versions
    • 3.5-1
    • 3.6.5-1
    • 3.6.7-1
    • 3.7-1
    • 3.7-1ubuntu0.1~esm1
    • 3.7-1ubuntu0.1~esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Ubuntu:Pro:24.04:LTS

    Versions
    • 3.8.1-1
    • 3.8.1-1ubuntu0.1~esm1
    • 3.8.1-1ubuntu0.1~esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Ubuntu:25.10

    Versions
    • 3.9.1-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Ubuntu:26.10

    Versions
    • 3.9.2-1
    • 3.9.3-1
    • 3.10.0-1
    • 3.10.1-1
    • 3.10.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • nltk Ubuntu:Pro:26.04:LTS

    Versions
    • 3.9.1-2
    • 3.9.1-2build1
    • 3.9.2-1
    • 3.9.2-1ubuntu0.1~esm1
    • 3.9.2-1ubuntu0.1~esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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