CVE-2026-54293
NLTK: URL-Encoded Path Traversal in nltk.data.load() Allows Arbitrary Local File Read
At a glance
- Source
- NVD
- EPSS
- EPSS 0.63 % · percentile 50 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
Description
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.
Weaknesses (CWE)
- CWE-22 — Improper Limitation of a Pathname to a Restricted Directory
References
- https://github.com/nltk/nltk/security/advisories/GHSA-p4gq-832x-fm9v
- https://github.com/nltk/nltk/pull/3575
- https://access.redhat.com/security/cve/CVE-2026-54293
- https://bugzilla.redhat.com/show_bug.cgi?id=2491486
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-54293.json
- https://access.redhat.com/errata/RHSA-2026:42644
- https://access.redhat.com/errata/RHSA-2026:65126
- https://access.redhat.com/errata/RHSA-2026:60520
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | redhat-SADP |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Advisories
- GHSA-p4gq-832x-fm9v — Natural Language Toolkit (NLTK): URL-Encoded Path Traversal in nltk.data.load() Allows Arbitrary Local File Read
- PYSEC-2026-2078 — NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Proce
European references
- ENISA EUVD · EUVD-2026-38333
- GCVE · GCVE-0-2026-54293
CERT-FR advisories
- CERTFR-2026-AVI-1378 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1206 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1094 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*< 3.10.0
Affected products
| Product | Versions |
|---|---|
| nltk · nltk | affected < 3.10.0-rc1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |