CVE-2026-12252Public exploit

Arbitrary code execution via unverified Stanford JARs

Published Jul 4, 2026 · Updated Jul 4, 2026

Code injection in NLTK 3.9.3 and earlier allows local users to execute arbitrary code through a supplied Stanford JAR file. Five Stanford interface classes pass user-controlled JAR paths to java(), which invokes subprocess.Popen() without verifying integrity. Execution requires an application or user to select or replace a JAR path; the bytecode runs with the Python process's privileges.

CVSS severity7.8
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in NLTK 3.9.3 and earlier allows local users to execute arbitrary code through a supplied Stanford JAR file. Five Stanford interface classes pass user-controlled JAR paths to java(), which invokes subprocess.Popen() without verifying integrity. Execution requires an application or user to select or replace a JAR path; the bytecode runs with the Python process's privileges.

The record

CVE
CVE-2026-12252
Published
Jul 4, 2026
Updated
Jul 4, 2026
Vendor
NLTK Project
Product
NLTK
Classifications
CWE-94, CWE-347, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=latest

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

NLTK Project · NLTKversion=unspecified <=latest

Published CVSS scores

7.8CNACVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8Red HatCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code
CWE-347Improper Verification of Cryptographic Signature
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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