GHSA-9r6g-266r-89x4: nltk (CVE-2026-12252)

In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vul...

CVSS 7.8 HighEPSS 0.0019 · 9th percentile

Published by the GitHub Advisory Database at 4 Jul 2026, 02:16 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
nltk	PyPI	<3.9.4	3.9.4

Identifiers

GHSA-9r6g-266r-89x4 · CVE-2026-12252 · PYSEC-2026-2085

Weakness (CWE)

CWE-94

Machine-written summary

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

Versions of nltk 3.9.3 and earlier have five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) that run user-supplied JAR files without integrity checks. An attacker who can get the application to load a malicious JAR may be able to execute arbitrary code. Upgrade nltk to version 3.9.4 or later.

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
7.8	High	3.0	CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H	CNA (@huntr_ai)

CISA KEV Not listed.
EPSS 0.0019, the 9th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:08 UTC First seen by agentprime
31 Oct 2026, 14:08 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.