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HIGH

CVE-2026-0847

Path Traversal in nltk/nltk

CVSS v3

7.5

HIGH

EPSS Score

0.9 %

exploit probability, as of 2026-10-16

CISA KEV

No

known exploited

Exploitation

poc

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • nltkPyPIall versions · fixed in 3.9.3

Vendor advisories

  • CVE-2026-0847 Red Hat Product Security4 products fixed · 6 known affected

    nltk: NLTK: Arbitrary file read via path traversal vulnerability

    lightspeed-core/lightspeed-stack-rhel9 as a component of Lightspeed Core · openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 as a component of OpenShift Lightspeed · openshift-lightspeed/lightspeed-service-api-rhel9 as a component of OpenShift Lightspeed

  • RHSA-2026:19712 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: RHOAI 3.3.3 - Red Hat OpenShift AI

  • RHSA-2026:10184 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: RHOAI 2.25.5 - Red Hat OpenShift AI

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Published
2026-03-04
Last Modified
2026-04-28

Frequently asked questions

What is CVE-2026-0847?

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.

Is CVE-2026-0847 actively exploited?

A proof-of-concept exploit exists for CVE-2026-0847, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-0847?

CVE-2026-0847 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

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