A vulnerability in the `filestring()` function of the `nltk.util` module in nltk version 3.9.2 allows arbitrary file read due to improper validation of input paths. The function directly opens files specified by user input without sanitization, enabling attackers to access sensitive system files by providing absolute paths or traversal paths. This vulnerability can be exploited locally or remotely, particularly in scenarios where the function is used in web APIs or other interfaces that accept user-supplied input.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8302-1 advisory.

    It was discovered that NLTK incorrectly validated file paths when opening files using the nltk.util     module. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-0846)

    It was discovered that NLTK incorrectly validated file paths in multiple CorpusReader classes. An attacker     could possibly use this issue to obtain sensitive information. (CVE-2026-0847)

    It was discovered that NLTK did not properly validate external Java archive files loaded by     StanfordSegmenter. An attacker could possibly use this issue to execute arbitrary code. This issue only     affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS.
    (CVE-2026-0848)

    It was discovered that NLTK's WordNet browser application incorrectly handled user-supplied input. An     attacker could possibly use this issue to perform a cross-site scripting attack. (CVE-2026-33230)

    It was discovered that NLTK's WordNet browser application did not restrict access to the shutdown     endpoint. A remote attacker could possibly use this issue to cause a denial of service. (CVE-2026-33231)

    It was discovered that NLTK's downloader did not validate path attributes in remote XML index files. An     attacker could possibly use this issue to create or overwrite arbitrary files. (CVE-2026-33236)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - A vulnerability in the `filestring()` function of the `nltk.util` module in nltk version 3.9.2 allows
    arbitrary file read due to improper validation of input paths. The function directly opens files specified
    by user input without sanitization, enabling attackers to access sensitive system files by providing
    absolute paths or traversal paths. This vulnerability can be exploited locally or remotely, particularly
    in scenarios where the function is used in web APIs or other interfaces that accept user-supplied input.
    (CVE-2026-0846)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A vulnerability in the `filestring()` function of the `nltk.util` module in nltk version 3.9.2 allows     arbitrary file read due to improper validation of input paths. The function directly opens files specified     by user input without sanitization, enabling attackers to access sensitive system files by providing     absolute paths or traversal paths. This vulnerability can be exploited locally or remotely, particularly     in scenarios where the function is used in web APIs or other interfaces that accept user-supplied input.
    (CVE-2026-0846)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
316734	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : NLTK vulnerabilities (USN-8302-1)	Nessus	Ubuntu Local Security Checks	high
440666	SCA: security update for nltk (GHSA-h8wq-7xc4-p3qx)	Tenable Cloud Security	SCA Checks	high
440666	SCA: security update for nltk (GHSA-h8wq-7xc4-p3qx)	Tenable Self-Hosted Container Security	SCA Checks	high
301683	Linux Distros Unpatched Vulnerability : CVE-2026-0846	Nessus	Misc.	high

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CVE-2026-0846

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Tenable Plugins

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