Is This vulnerability exploited in the wild?

No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

How severe is This vulnerability?

High severity, with a CVSS score of 7.8, published 25 August 2026.

Is there a fix for This vulnerability?

A patch was published on 2026-08-25: Fix released in NLTK 3.10.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is This vulnerability attacked?

It is attacked with local access.

Check whether you run nltk (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

NLTK untrusted search path in Graphviz dot invocation

Severity: high · CVSS 7.8 · Published 2026-08-25

NLTK is a Python library for natural language processing. Versions before 3.10.3 fail to validate the absolute path when invoking the Graphviz dot binary for visualizing dependency graphs and rendering aligned sentence output, allowing an attacker with local access to execute arbitrary code by placing a malicious dot binary in the current directory or writable PATH locations. This could lead to complete system compromise if NLTK is used in a context where untrusted code or data is processed.

Technologies: nltk (PyPI). Vendors: PyPI.

Quick answers

Is This vulnerability exploited in the wild?: No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?: High severity, with a CVSS score of 7.8, published 25 August 2026.
Which products and versions are affected?: nltk (PyPI) <= 3.10.2.
Is there a fix for This vulnerability?: A patch was published on 2026-08-25: Fix released in NLTK 3.10.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?: It is attacked with local access.
Am I affected?: Check whether you run nltk (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

This is a path injection vulnerability (CWE-426, CWE-427) in NLTK's invocation of the Graphviz dot binary. The vulnerable code paths are in nltk.parse.dependencygraph.dot2img and nltk.translate.api.AlignedSent._repr_svg_, which either call find_binary("dot") but then execute the bare name ["dot", ...] instead of the validated path, or execute the bare name with no validation at all. On Windows, the current working directory (CWD) is checked first in binary resolution; on Unix-like systems, relative PATH entries like "." are searched. An attacker with local access can place a malicious dot binary in the CWD or a writable PATH directory to achieve arbitrary code execution under the privileges of the NLTK process. The fix, available in version 3.10.3, uses the validated absolute path returned by find_binary instead of the bare tool name. Low privileges are required to exploit this (the user must be able to write to the working directory or modify PATH), and there is no user interaction needed once the malicious binary is in place.

Affected products

NLTK NLTK <= 3.10.2

Timeline

2026-08-25: disclosed
2026-08-25: patched: Fix released in NLTK 3.10.3
2026-09-01: advisory: Original advisory GHSA-54xp-3ww7-6wjg withdrawn as duplicate of GHSA-6hwm-xvph-95vm on Sep 1, 2026

References

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