CVE-2025-71408Public exploit

Local code execution via evaluated CLI arguments

Published Jul 24, 2026 · Updated Jul 24, 2026

Eval injection in NLTK before 3.9.3 allows local users to execute arbitrary Python code via crafted collocations CLI arguments. The nltk.collocations main block concatenates each untrusted argument to BigramAssocMeasures and evaluates the resulting expression rather than restricting it to an attribute name. Exploitation requires the ability to supply arguments when the module is launched directly and runs code with that process's privileges.

CVSS severity8.5
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Eval injection in NLTK before 3.9.3 allows local users to execute arbitrary Python code via crafted collocations CLI arguments. The nltk.collocations main block concatenates each untrusted argument to BigramAssocMeasures and evaluates the resulting expression rather than restricting it to an attribute name. Exploitation requires the ability to supply arguments when the module is launched directly and runs code with that process's privileges.

The record

CVE
CVE-2025-71408
Published
Jul 24, 2026
Updated
Jul 24, 2026
Vendor
NLTK Project
Product
NLTK
Classifications
CWE-95, T1059.006
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 24, 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=0 <3.9.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

NLTK Project · NLTKversion=0 <3.9.3

Published CVSS scores

8.5VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.8VulnCheckCVSS:3.1/AV:L/AC:L/PR:L/UI:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-95Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')
T1059.006Command and Scripting Interpreter: Python

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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