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Vulnerability record · CVE-2026-70626 · published 22 August 2026

CVE-2026-70626: Nltk link following vulnerability

Nltk · Nltk

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.

8.6 CVSS 4.0 High EPSS 0.20% · top 91.2% CWE-59 · Link following
8.6CVSS 4.0 base score
0.20%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 2 tagged exploit
31 Aug 2026Last modified by NVD

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.

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/nltk/nltk/security/advisories/GHSA-r6gq-whwq-mvg9 ExploitVendor Advisory
https://www.vulncheck.com/advisories/nltk-before-symlink-escape-via-corpusreader Vendor Advisory
https://github.com/nltk/nltk/security/advisories/GHSA-r6gq-whwq-mvg9 ExploitVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-70626), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.