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Fencer Vulns
high 8.6

CVE-2026-0847 json

Path Traversal in nltk/nltk

published 2026-03-04 8 mo ago modified 2026-11-04 5 d ago also GHSA-68j8-pq59-fqgm , PYSEC-2026-98 , EUVD-2026-9475

cvss
8.6
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.

Patch / fix

  • pypi nltk 3.9.3
  • Red Hat Red Hat OpenShift AI 2.25 1775144403
  • Red Hat Red Hat OpenShift AI 3.3 1778262893, 1778263054
  • nltk Debian 14 3.9.3-1

debian advisories DEBIAN-CVE-2026-0847

  • nltk Ubuntu Pro 14.04 LTS 2.0~b9-0ubuntu4.1~esm6
  • nltk Ubuntu Pro 16.04 LTS 3.1-1ubuntu0.1+esm4
  • nltk Ubuntu Pro 18.04 LTS 3.2.5-1ubuntu0.1+esm4
  • nltk Ubuntu Pro 20.04 LTS 3.4.5-2ubuntu0.1~esm4
  • nltk Ubuntu Pro 22.04 LTS 3.7-1ubuntu0.1~esm2
  • nltk Ubuntu Pro 24.04 LTS 3.8.1-1ubuntu0.1~esm2
  • nltk Ubuntu Pro 26.04 LTS 3.9.2-1ubuntu0.1~esm2

ubuntu advisories UBUNTU-CVE-2026-0847

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python-nltk openSUSE Tumbleweed 3.9.3-1.1

opensuse advisories openSUSE-SU-2026:10304-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-0847 updated cvss 7.5

nltk: NLTK: Arbitrary file read via path traversal vulnerability

  • Red Hat Lightspeed Core lightspeed-core/lightspeed-stack-rhel9
    affected: no fix available
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9
    affected: no fix planned “Will not fix”
  • Red Hat Ansible Automation Platform 2 ansible-automation-platform-25/lightspeed-chatbot-rhel8, ansible-automation-platform-26/lightspeed-chatbot-rhel9
    affected: no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-ta-lmes-job-rhel9
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift AI 2.25 rhoai 1775144403
    fixed: vendor fix RHSA-2026:10184
  • Red Hat OpenShift AI 3.3 rhoai 1778262893, rhoai 1778263054
    fixed: vendor fix RHSA-2026:19712
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9 Red Hat Ansible Automation Platform 2 ansible-automation-platform/ee-minimal-rhel8, ansible-automation-platform/ee-minimal-rhel9, ansible-automation-platform-24/de-minimal-rhel8, ansible-automation-platform-24/de-minimal-rhel9, ansible-automation-platform-24/ee-minimal-rhel8, ansible-automation-platform-24/ee-minimal-rhel9, +21 more Red Hat OpenShift AI 2.25 rhoai 1776243157, rhoai 1776243163, rhoai 1776243192, rhoai 1776243217, rhoai 1776243229, rhoai 1776243238, +70 more Red Hat OpenShift AI 3.3 rhoai 1778239104, rhoai 1778262829, rhoai 1778262856, rhoai 1778262907, rhoai 1778262952, rhoai 1778262982, +74 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

1.00% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.com https://huntr.com/bounties/fc69914f-36a9-4c18-8503-10013b39f966 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 8.6 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub 3.0 8.6 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi nltk
<3.9.3
3.9.3

Affected products

  • nltk nltk/nltk
  • Red Hat Red Hat OpenShift AI 2.25
  • Red Hat Red Hat OpenShift AI 3.3
  • Red Hat Lightspeed Core
  • Red Hat OpenShift Lightspeed
  • Red Hat Red Hat Ansible Automation Platform 2
  • Red Hat Red Hat OpenShift AI (RHOAI)

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.