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Fencer Intel
high 7.0

CVE-2026-81726 json

NLTK through 3.10.3 Path Traversal via Model-Artifact APIs

published 2mo ago modified 9d ago also EUVD-2026-67076 , GHSA-8mgp-746c-j5xp , PYSEC-2026-3740

cvss
7.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits
0
none known

Summary

NLTK through 3.10.3 contains a path traversal vulnerability in model-artifact APIs that bypass pathsec enforcement by using raw file operations on caller-controlled paths. Attackers can read or write files outside allowed sandbox roots through TransitionParser, AveragedPerceptron, PerceptronTagger, and maxent parameter APIs when pathsec is enabled.

Patch / fix

  • pypi nltk 3.10.3, 3.10.4
  • nltk nltk 3.10.4
  • python-nltk openSUSE Tumbleweed 3.10.4-1.1

opensuse advisories openSUSE-SU-2026:12280-1

Is CVE-2026-81726 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-81726 updated cvss 8.7

nltk: NLTK: Unauthorized file access via path traversal in model-artifact APIs

  • Red Hat Exploit Intelligence exploit-intelligence-tech-preview/vulnerability-analysis-rhel9
    affected: workaround, no fix planned “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.”
  • Red Hat Lightspeed Core lightspeed-core/rag-tool-cpu-rhel9, lightspeed-core/lightspeed-stack-rhel9, lightspeed-core/rag-tool-cuda-12.9-rhel9
    affected: workaround, no fix available “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.”
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-service-api-rhel9 Red Hat Ansible Automation Platform 2 ansible-automation-platform-25/lightspeed-chatbot-rhel8
    affected: workaround, no fix planned “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-pipeline-runtime-pytorch-llmcompressor-cuda-py312-rhel9, rhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9
    affected: workaround, no fix available “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.”
  • Red Hat OpenShift AI 3.4 rhoai/odh-ta-lmes-job-rhel9 1791470318, rhoai/odh-llama-stack-core-rhel9 1790958470, rhoai/odh-trustyai-garak-lls-provider-dsp-rhel9 1791785804, rhoai/odh-trustyai-nemo-guardrails-server-rhel9 1791556128
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.” RHSA-2026:84734
  • Red Hat OpenShift AI 3.5 rhoai/odh-ogx-core-rhel9 1790963109, rhoai/odh-trustyai-nemo-guardrails-server-rhel9 1791566631
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.” RHSA-2026:86891
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat OpenShift AI 3.4 rhoai/odh-cli-rhel9 1791509689, rhoai/rhai-cli-rhel9 1791509689, rhoai/odh-automl-rhel9 1791535789, rhoai/odh-mlflow-rhel9 1791865967, rhoai/odh-autorag-rhel9 1791557539, rhoai/odh-trainer-rhel9 1791869783, +96 more Red Hat OpenShift AI 3.5 rhoai/odh-cli-rhel9 1791945905, rhoai/rhai-cli-rhel9 1791945905, rhoai/odh-automl-rhel9 1791916705, rhoai/odh-mlflow-rhel9 1791947857, rhoai/odh-autorag-rhel9 1791903266, rhoai/odh-trainer-rhel9 1791952138, +111 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/nltk/nltk/security/advisories/GHSA-8mgp-746c-j5xp referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.3 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N
CNA 3.1 7.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:L
GitHub 3.1 7.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:L
CNA 4.0 8.3 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
pypi nltk
<3.10.4
<3.10.3
3.10.4
3.10.3

Affected products

  • nltk nltk

Classification

Weakness
  • CWE-73 External Control of File Name or Path
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-59 Improper Link Resolution Before File Access

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of nltk/nltk published their own advisory on GitHub. Reviewed sources take precedence over it.