GHSA-6hm5-jgcp-p838: nltk (CVE-2026-12072)

Natural Language Toolkit (NLTK): Path Traversal in NKJPCorpusReader leads to Arbitrary File Read and bypasses the nltk.pathsec sandbox (ENFORCE=True)

CVSS 7.5 High

Published by the GitHub Advisory Database at 31 Jul 2026, 16:50 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
nltk	PyPI	<3.10.0	3.10.0

Identifiers

GHSA-6hm5-jgcp-p838 · CVE-2026-12072 · PYSEC-2026-3581

Weakness (CWE)

CWE-22

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Path traversal in NLTK's NKJPCorpusReader lets an attacker who can control the fileids argument of its read methods (header, raw, words, sents, tagged_words) read files outside the corpus root, bypassing the nltk.pathsec sandbox even with ENFORCE=True. Affected versions are nltk before 3.10.0. Upgrade to nltk 3.10.0 or later; no other workaround is given beyond not passing untrusted values into fileids.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.5	High	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	GitHub Advisory Database

CISA KEV Not listed.
EPSS No score.

Timeline

31 Oct 2026, 14:11 UTC First seen by agentprime
31 Oct 2026, 14:11 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.