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TI-2026-50115 Aliases CVE-2026-71513GHSA-5gh2-94qg-qppq

NLTK 3.10.0 through 3.10.2 Remote Code Execution via AllowlistUnpickler Dotted-Name Bypass

Priority MEDIUM 42CWE-502Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 2 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-502.

Summary

NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables outside the allowlisted namespace. Attackers can craft untrusted transition-parser models that execute arbitrary commands when TransitionParser.parse loads the model through allowlisted_pickle_load.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01097 65th percentileScored 2026-11-07
Fix Partial nltk (nltk): 3.10.3nltk (PyPI): 3.10.3Red Hat: 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nltknltk3.10.0 to before 3.10.33.10.3Patch availableCNA
—nltk (PyPI)3.10.0 to before 3.10.33.10.3Patch availableGHSA-5gh2-94qg-qppq
  • nltk Vendornltk Affected 3.10.0 to before 3.10.3 Fixed in 3.10.3 Patch available CNA
  • nltk (PyPI) Vendor— Affected 3.10.0 to before 3.10.3 Fixed in 3.10.3 Patch available GHSA-5gh2-94qg-qppq

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*before 3.10.3Vulnerablenltk
  • cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:* Versions before 3.10.3 Vulnerable ·nltk

Remediation

  • Fix · CNA nltk (nltk) Fixed in 3.10.3
  • Fix · GHSA-5gh2-94qg-qppq nltk (PyPI) Fixed in 3.10.3 Advisory →

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    nltk 3.10.3

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-50116 NLTK 3.9.4 through 3.10.2 Path Traversal via CrubadanCorpusReader pathsec BypassPriority LOW 10
    Show all 2 records →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Lightspeed CoreAffectedNo fix yet
OpenShift LightspeedAffectedNo fix yet
Not affected: 4 products
  • Exploit Intelligence
  • OpenShift Lightspeed
  • Red Hat Ansible Automation Platform 2
  • Red Hat OpenShift AI (RHOAI)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-71513
  2. 2026-10-03 Alias added: GHSA-5gh2-94qg-qppq

References

Patch 1

Advisory 1

Other 2

  • TI-2026-00629 Arbitrary Code Execution in NLTK StanfordSegmenter via Untrusted JAR Loading CVSS 3.0CRITICAL 10.0
  • TI-2025-12800 Zip Slip Vulnerability in nltk/nltk Leading to Remote Code Execution CVSS 3.0CRITICAL 10.0
  • TI-2026-55173 NLTK before 3.10.3 JVM Argument Injection via Per-Call Options CVSS 4.0CRITICAL 9.3
  • TI-2026-55155 NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization CVSS 4.0CRITICAL 9.3
  • TI-2026-56370 nltk PorterStemmer before 3.10.3 Quadratic-time DoS CVSS 4.0HIGH 8.7
  • TI-2026-55172 NLTK 3.10.2 Path Traversal via corpus-reader constructors CVSS 4.0HIGH 8.8
See all 41 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences