CVE-2026-70626

Medium

Description

NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.

SeverityMedium

CVSS6.2

Exploit probability—

ProductNltk

PublishedAug 22, 2026

First seenAug 22, 2026

Weakness typeCWE-59Improper link resolution

How to fix

Update

nltk nltk3.9.4 or later
nltk3.9.4 or later

Vendor advisories

github.com/nltk/nltk/security/advisories/GHSA-r6gq-whwq-mvg9

Affected products

Product	Affected versions	Fixed in
nltk nltk	v < 3.9.4	3.9.4
nltkPyPI	v < 3.9.4	3.9.4

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