Unrated

NLTK Stanford Wrapper JVM Argument Injection

IdentifiersCVE-2026-12841CWE-88

NLTK before 3.10.3 incompletely validates JVM arguments supplied through the per-call options parameter of nltk.internals.java(). User-controlled java_options passed by GenericStanfordParser, StanfordTagger, StanfordTokenizer, or StanfordSegmenter can bypass the intended JVM-option validation, allowing injection of arbitrary JVM flags.

For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

Start free trial

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

An attacker who controls per-call JVM options can supply dangerous JVM flags. Depending on the Java runtime and supplied arguments, this can load native or Java agents, process attacker-controlled argument files, or expose a JDWP debugging interface. These conditions may result in arbitrary code execution.

Mitigation

If you can’t patch tonight, do this now.

Do not derive java_options from untrusted requests, configuration, or environment variables. Until upgrades are complete, apply _validate_java_options() to per-call options and enforce a restrictive allowlist that excludes agent-loading, JDWP, and argument-file flags. Restrict access to Java debugging ports and run affected services with least privilege.

Remediation

Patch, then assume compromise.

Upgrade the PyPI nltk package to version 3.10.3 or later. The fix validates per-call java_options by invoking _validate_java_options() within nltk.internals.java() when an options argument is supplied.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

NLTK ProjectNltkapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

2 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

2 SOURCESView more in app

ghsa syntheticNews

Sep 1, 2026

GHSA-m4rf-3fr8-xwx3

A prior NLTK JVM argument-injection vulnerability whose incomplete remediation is bypassed through unvalidated per-call Java options.

ghsa syntheticNews

Aug 25, 2026

GHSA-3h2g-j4wp-7qqq

JVM argument-injection vulnerability in NLTK Stanford wrappers. NLTK versions through 3.10.2 do not validate per-call JVM options passed to java(), enabling injection of dangerous JVM flags and arbitrary code execution.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

Start free trial

Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity